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THE  WORLD  OF   LIFE 


THE    WORLD    OF    LIFE 


A    MANIFESTATION    OF 

CREATIVE    POWER,    DIRECTIVE    MIND 

AND    ULTIMATE    PURPOSE 


BY 

ALFRED  RUSSEL  WALLACE 

O.M.,    F.R.S.,    D.C.L.,    Etc. 


NEW    YORK 
MOFFAT,   YARD    &    COMPANY 

I  9  I  I 


Copyright,  1910,  191 1,  by 

Moffat,  Yard  and  Company 

New   York 


All  Rights  Reserved 
Published  January,  191 1 


PEEFACE 

In  the  present  volume  I  have  attempted  to  summarise  and 
complete  my  half-century  of  thought  and  work  on  the  Dar- 
winian theory  of  evolution.  In  several  directions,  I  have 
extended  the  scope  and  application  of  the  theory,  and  have 
shown  that  it  is  capable  of  explaining  many  of  the  phenomena 
of  living  things  hitherto  thought  to  be  beyond  its  range. 

Among  these  are  the  detailed  distribution  of  plants  and 
animals,  which  I  have  discussed  at  some  length.  It  occupies 
about  one-fourth  of  the  volume  (Chapters  II.  to  VI.)?  and 
brings  out  certain  facts  and  conclusions  which  I  believe  mil 
be  of  interest  to  all  plant-lovers,  and  also  be  not  without  a 
certain  value  to  botanists. 

'Next  in  importance  are  three  chapters  (X.,  XL,  and  XII.) 
devoted  to  a  general  review  of  the  Geological  Eecord  and  a 
discussion  of  the  various  problems  arising  out  of  it.  Some 
of  the  conclusions  to  which  this  examination  leads  us  are,  I 
believe,  both  important  and  of  much  general  interest. 

In  Chapter  VIII.  I  have  endeavoured  to  show  natural  selec- 
tion actually  at  work  in  the  continually  perfecting  that  won- 
derful co-adaptation  of  the  most  diverse  forms  of  life  which 
pervades  all  nature.  Some  little-known  aspects  of  bird-migra- 
tion are  here  discussed,  and  proof  is  given  of  the  enormous 
importance  of  mosquitoes  for  the  very  existence  of  considerable 
proportion  of  our  birds,  including  most  of  our  most  favoured 
pets  and  songsters.  This  chapter  will,  I  think,  have  a  special 
interest  for  every  bird-lover. 

106920 


yi  THE  WOKLD  OF  LIFE 

In  Chapter  IX.  I  deal  with  some  little-known  phenomena 
in  that  hitherto  neglected  field  of  enquiry  which  I  have  termed 
"  Eecognition  Marks."  Besides  the  obvious  uses  implied  by 
their  name,  I  have  shown  that  they  are  of  great  importance  — 
perhaps  absolutely  essential  —  in  the  process  of  the  evolution 
of  new  species.  During  the  enquiry  I  have  arrived  at  the 
somewhat  startling  conclusion  that  the  exquisite  variety  and 
beauty  of  insect-coloration  and  marking  have  not  been  devel- 
oped through  their  ovni  visual  perceptions,  but  mainly  —  per- 
haps even  exclusively  —  through  those  of  higher  animals.  I 
show  that  brilliant  butterflies  do  not,  and  almost  certainly 
cannot,  recognise  each  other  by  colour,  and  that  they  probably 
do  not  even  perceive  colour  at  all  except  as  to  a  certain  extent 
presenting  visual  differences. 

But  besides  the  discussion  of  these  and  several  other  allied 
subjects,  the  most  prominent  feature  of  my  book  is  that  I  enter 
into  popular  yet  critical  examination  of  those  underlying  funda- 
mental problems  which  Darwin  purposely  excluded  from  his 
"works  as  being  beyond  the  scope  of  his  enquiry.  Such  are  the 
nature  and  causes  of  Life  itself,  and  more  especially  of  its 
most  fundamental  and  mysterious  powers  —  growi:h  and  repro- 
duction. 

I  first  endeavour  to  show  (in  Chapter  XIV.)  by  a  careful 
consideration  of  the  structure  of  the  bird's  feather ;  of  the 
marvellous  transformations  of  the  higher  insects ;  and,  more 
especially  of  the  highly  elaborated  wing-scales  of  the  Lepidop- 
tera  (as  easily  accessible  examples  of  what  is  going  on  in  every 
part  of  the  structure  of  every  living  thing),  the  absolute  neces- 
sity for  an  organising  and  directive  Life-Principle  in  order  to 
account  for  the  very  possibility  of  these  complex  out-growths. 


PEEFACE 


Vll 


I  argue  that  they  necessarily  imply  first,  a  Creative  Power, 
which  so  constituted  matter  as  to  render  these  marvels  pos- 
sible; next,  a  directive  Mind,  which  is  demanded  at  every  step 
of  the  process  we  term  growth  and  often  look  upon  as  so 
simple  and  natural  a  process  as  to  require  no  explanation; 
and,  lastly,  an  ultimate  Purpose,  in  the  very  existence  of  the 
whole  vast  life-world  in  all  its  long  course  of  evolution  through- 
out the  eons  of  geological  time.  This  Purpose,  which  alone 
throws  light  on  many  of  the  mysteries  of  its  mode  of  evolu- 
tion, I  hold  to  be  the  development  of  Man,  the  one  crowning 
product  of  the  whole  cosmic  process  of  life-development;  the 
only  being  which  can  to  some  extent  comprehend  nature ;  which 
can  perceive  and  trace  out  her  modes  of  action ;  which  can 
appreciate  the  hidden  forces  and  motions  everywhere  at  w^ork, 
and  can  deduce  from  them  all  a  supreme  and  overruling  mind 
as  their  necessary  cause. 

If  we  accept  some  such  view  as  I  have  now  indicated,  I 
show  (in  Chapters  XV.  and  XVI.)  how  strongly  it  is  sup- 
ported and  enforced  by  a  long  series  of  facts  and  co-relations 
which  we  can  hardly  look  upon  as  all  purely  accidental  coin- 
cidences. Such  are  the  infinitely  varied  products  of  living 
things  which  serve  man's  purposes  and  man's  alone  —  not  only 
by  supplying  his  material  wants,  and  by  gratifying  his  higher 
tastes  and  emotions,  but  as  rendering  possible  many  of  those 
advances  in  the  arts  and  in  science  which  we  claim  to  be  the 
highest  proofs  of  his  superiority  to  the  brutes  and  of  his 
advancing  civilisation. 

From  a  consideration  of  these  better-knoAvn  facts  I  proceed 
(in  Chapter  XXII.)  to  an  exposition  of  the  mystery  of  cell- 
growth;  to  a  consideration  of  the  elements  in  their  special 
relation  to  the  earth  itself  and  to  the  life-world ;  while  in  the 


viii  THE  WORLD  OE  LIFE 

last  chapter  I  endeavour  to  show  the  purpose  of  that  law  of 
diversity  which  seems  to  pervade  the  whole  material  Universe. 
As  an  ''  excursus,"  I  devote  Chapter  XIX.  to  a  discussion  of 
the  nature,  extent,  and  uses  of  Pain,  as  strictly  deduced  from 
the  law  of  Evolution.  Strangely  enough,  this  has  never,  I 
believe,  been  done  before ;  and  it  enables  us  to  answer  the 
question  — ^'  Is  Xature  Cruel  ?  "  with  a  decided  negative. 

This  outline  of  the  varied  contents  and  objects  of  my  book, 
wdll,  I  hope,  be  useful  to  my  readers,  and  especially  to  my 
reviewers,  by  directing  their  attention  to  those  parts  of  the 
work  in  which  they  may  be  more  especially  interested. 

I  also  wish  to  point  out  that,  however  strange  and  heretical 
some  of  my  beliefs  and  suggestions  may  appear  to  be,  I  claim 
that  they  have  only  been  arrived  at  by  a  careful  study  of  the 
facts  and  conditions  of  the  problem.  I  mention  this  because 
numerous  critics  of  my  former  work  —  Man's  Place  in  the 
Universe  (to  which  this  may  be  considered  supplementary)  — ■ 
treated  the  conclusions  there  arrived  at  as  if  they  were  wholly 
matters  of  opinion  or  imagination,  and  founded  (as  were  their 
own)  on  personal  likes  or  dislikes,  without  any  appeal  to  evi- 
dence or  to  reasoning. 

I  have  now  only  to  express  my  thanks  to  the  friends  and 
strangers  who  have  kindly  assisted  me  with  numerical  and 
other  data  for  various  portions  of  my  work ;  as  well  as  to  those 
publishers  and  authors  who  have  allowed  me  to  use  the  en- 
gravings or  photographs  with  which  my  book  is  illustrated. 
They  are  in,  every  case  (I  believe)  acknowledged  in  the  text, 
or  on  the  various  plates  and  figures. 


Broadstone,  Wimborne, 
November   1910. 


CONTENTS 

CHAPTER  I 

PAGE 

What  is  Life  and  Whence  it  Comes 1 

CHAPTER  II 
Species  —  their  Numbers,  Variety,  and  Distribution  ...     12 

CHAPTER  III 

The   Numerical   Distribution   of   British    Plants :    Temperate 
Floras   Compared 24 

CHAPTER  IV 
The  Tropical  Floras  of  the  World •     .      .     43 

CHAPTER  V 
The  Distribution  of  Animals 89 

CHAPTER  VI 

The  Numerical  Distribution  of  Species  in  Relation  to  Evolu- 
tion      100 

CHAPTER  VII 
Heredity,  Variation,  Increase 109 

CHAPTER  VIII 

Illustrative  Cases  of  Natural  Selection  and  Adaptation     .      .   134 

ix 


X  THE  WORLD  OF  LIPE 

CHAPTEE  IX ' 


PAGE 


The  Importance  of  Eecognition-marks  in  Evolution     .      .      .168 

CHAPTEE  X 

The  Earth's  Surface-changes  the  Motive  Power  of  Evolution  187 

CHAPTEE  XI 

The   Progressive   Development  of   the   Life-World   as   shown 
by  the  Geological  Eecord 303 

CHAPTEE  XII 
Life  of  the  Tertiary  Period 235 

CHAPTEE  XIII 
Some  Extensions  of  Darwin's  Theory     .......  371 

CHAPTEE  XIY 

Birds  and  Insects  as  Proofs  of  an  Organising  and  Directive 
Life-principle 309 

CHAPTEE  XV 

General  Adaptation  of  Plants,  Animals,  and  Man  .      .      .      .321) 

CHAPTEE  XVI 

The  Vegetable  Kingdom  in  its  special  Eelation  to  Man  .      .   350 

CHAPTEE  XVII 
The  Mystery  of  the  Cell 361 


CONTENTS  xi 

CHAPTER  XVIII 

PAGE 

The  Elements  and  Water  in  Eelation  to  the  Life-AYorld  .      .   383 

CHAPTER  XIX 
Is  Nature  Cruel?     The  Uses  of  Pain 398 

CHAPTER  XX 
Infinite  Variety  the  Law  of  the  Universe 415 


LIST  OF  ILLUSTRATIONS 

FIG.  PAGE 

1.  Forest  in  Kelantan,  Malay  Poninsula 48 

2.  Forest  in  Perak,  Malay  Peninsula 50 

3.  Campos  of  Lagoa  Santa,  Brazil GO 

4.  View  of  Campo  Cerrado,  Lagoa  Santa 70 

5.  View  at  Lapa  Vermelha  Eocks,  Lagoa  Santa   .      .      .  72 

6.  Casselia  chamaedrifoUa 73 

7.  Andira  laurifolia 74 

8.  A  Forest  Stream,  West  Java 80 

9.  Diagram  of  Curve  of  Stature IIG 

10.  Diagram  of  Variation 118 

11.  American   Bison 124 

12.  The   Lemming 129 

13.  Shooting  Wild  Cleese  at  the  Arctic  Circle   ....  147 

14.  Geese    Migrating 148 

15.  Mr.  Seebohm's  Mosquito  Veil 149 

16.  Watching  Grey  Plover  Among  Mosquitoes    ....  150 

17.  Ice  Breaking  up,  Petchora  Eiver 152 

18.  Midsummer  on  the  Tundra 153 

19.  Sudden  Arrival  of  Birds 154 

20.  Grey  Plover,  Xest  and  Young 156 

21.  The  Higher  Tundra 159 

22.  Migration  Xight  at  Heligoland 162 

23.  Mimicry  of  Wasp  by  a  Beetle 170 

24.  Tragelaphus  speJcei 1<4 

25.  Boocercus  euryceros 1<4 

26.  Gazella  granii 1^4 

27.  Gazelli  walleri l'^4 

28.  Strepsiceros  Jciidu 1^" 

29.  Strepsiceros  imherhis 1^6 

30.  Bubalis  JacTcsonia 1'^^ 

31.  ^pyceros  melampus 1*^6 

•  •  • 

Xlll 


xiv  THE  WORLD  OF  LIFE 


riG. 


PAGE 


32.  Cohus  leche 178 

33.  Cohus  defossa 178 

34.  Cohus  Maria 178 

35.  Oryx  Gazella 178 

36.  (E dicnertius  grallarius 176 

37.  (Edicnemus  magnirostris 176 

38.  Great  Indian  Stone  Curlew 177 

39.  Thelodus  scoticus 208 

40.  Pteraspis  rostrata 208 

41.  Cephalaspis  murchisoiii 209 

42.  Protocercal    Tail 209 

43.  Heterocercal    Tail 209 

44.  Homocercal   Tail 210 

45.  Pariasaurus  Bainii 214 

46.  Skull  of  Dicynodon  lacerticeps 214 

47.  Slvull  of  JEIusaurus  felinus 215 

48.  Skull  of  Inostransevia 216 

49.  Eestoration   of  Dimetrodon 216 

50.  Skeleton  of  Iguanodon 218 

51.  Eestoration  of  Iguanodon 218 

52.  Skull  of   Iguanodon 218 

53.  Skeleton  of  Armoured  Dinosaur 218 

54.  Skull  of  Horned  Dinosaur 219 

55.  Eestoration  of   Stegosaurus 220 

56.  Sauropodous  Dinosaur 221 

57.  Skeleton  of  Diplodocus  carnegii 222 

58.  Skull  of  Sauropodous  Dinosaur 222 

59.  Skull  of  a  Theropodous  Dinosaur 222 

60.  Outline  and  Skeleton  of  Plesiosaurus  macro cephalus       .  224 

61.  Outline  and  Skeleton  of  Ichthyosaurus  communis     .      .  224 

62.  Bones  and  Paddles  of  Ichthyosaurus 224 

63.  Skeleton  of  Pterodactylus  spectahilis 225 

64.  Eestoration  of  Rhymphorhynchus  phyllurus    ....  226 

65.  Toothless  Pterodactyl 226 

66.  Skull  of  Peteranodon  longiceps 227 

67.  Lower  Jaw  of  Phasolothcrium  huchlandi 228 

68.  Jaw  and  Teeth  of  Spalacotherium.  tricuspidens  .      •      •  228 


LIST  OF  ILLUSTRxVTIONS  xv 

FIG.  .                                                         PAGE 

69.  Jaw  of    Triconodon  mordax 228 

70.  Drawing  of  the  Fossil  Lizard-tailed  Bird     ....   230 

71.  Skull  of  Arcliccoptcryxsiemensi 231 

72.  Skeleton  of   Phenacodus  primwvus 232 

73.  Skeleton  of  Uintatherium  ingens 236 

74.  Skull  of  Uintatherium  cornutum 237 

75.  Skeleton  of  Titanotherium  rohustum 238 

76.  Skull  of  Arsinoitheriiim  zitteli 240 

77.  Skeleton  of  a  Creodont 242 

78.  Skeleton  of  Hyopotamus  brachyrhynchus 243 

79.  Anoplotherium  commune 244 

80.  Palwotheriiim  magnum 244 

81.  Skull  of  Moeriilierium  hjonsi 244 

82.  Skulls  of  Ancestral  Elephants 246 

83.  Skeleton  of  Tetrahelodon  angvstidens 246 

84.  Probable  Appearance  of  Tetrahelodon  augustidens    .      .    246 

85.  Skeleton  of  Mastodon  americanus 247 

^Q.  Skeleton  of  Mammoth  Elephas  promigenius   ....   249 

87.     Skeleton  of  Toxodon  platensis 250 

S8.     Skeleton  of   Glyptodon  clavipeR 253 

89.  Probable  Appearance  of  tlio   Giant  Ground-sloth    .      .   254 

90.  Mylodon  rohustus 254 

91.  Skeleton  of  Scelidotlierium  leptocephalum       ....    255 

92.  Skull  of  an  Extinct  Marsupial 257 

93.  Skull  of  Thylacoleo  carnifex 258 

94.  Sabre-toothed   Tiger 284 

95.  Skeleton  of  Giant  Deer 284 

96.  Conocoryphe  sultzeri       .» 287 

97.  Paradonides  hohemiciis  .      ♦ 287 

98.  Acidaspis  dufrenoyi 288 

99.  Ceratites  nodosus 289 

100.  Trachyceras  aon 28 J 

101.  Crioceras  emerici 289 

102.  Heieroceras  emerici 289 

103.  Macroscaphites  ivanii      .      .      o 290 

104.  Hamites  rotundus -^"^^ 

105.  Ptychoceras  emericiciniim '^•^^ 


xvi  THE  WORLD  OF  LIFE 

PAGE 

106.  Ancyloceroe  matheronianiinis 390 

107.  Head  of  Babirusa 296 

108.  Perspective  View  of  a  Part  of  a  Wing-feather  .      .      .313 

109.  Oblique  Section  Showing  how  the  Barbules  hook  To- 

gether   312 

110.  Diagram  of  Nuclear  Division 3 TO 


THE  WORLD  OF  LIFE 


CHAPTER    I 

WHAT    LIFE    IS,    AjI^D    WHENCE    IT    COMES 

When  primeval  man  first  rose  above  the  brutes  from  which 
he  was  developed ;  when,  by  means  of  his  superior  intellect, 
he  had  acquired  speech  and  the  use  of  fire ;  and  more  espe- 
cially when  his  reasoning  and  reflecting  faculties  caused  him 
to  ask  those  questions  which  every  child  now  asks  about  the 
world  around  it  —  what  is  this  ?  and  why  is  that  ?  —  he  would, 
for  the  first  time,  perceive  and  wonder  at  the  great  contrast 
between  the  living  and  the  not-living  things  around  him. 

He  would  first  observe  that  the  animals  which  he  caught 
and  killed  for  food,  though  so  unlike  himself  outwardly,  were 
yet  very  like  his  fellow-men  in  their  internal  structure.  He 
would  see  that  their  bony  framework  was  almost  identical  in 
shape  and  in  substance  with  his  own;  that  they  possessed  flesh 
and  blood,  that  they  had  eyes,  nose,  and  ears;  that  presumably 
they  had  senses  like  his  own,  sensations  like  his  own ;  that  they 
lived  by  food  and  drink  as  he  did,  and  yet  were  in  many  ways 
so  different.  Above  all,  he  would  soon  notice  how  inferior 
they  were  to  himself  in  intellect,  inasmuch  as  they  never  made 
fires,  never  used  any  kind  of  tools  or  weapons ;  and  that, 
although  many  of  them  were  much  stronger  than  he  was,  yet 
his  superiority  in  these  things,  and  in  making  traps  or  pitfalls 
to  capture  them,  showed  that  he  was  really  their  superior  and 
their  master. 

Gradually,  probably  very  slowly,  he  would  extend  these 
observations  to  all  the  lower  forms  of  life,   even  wdjen  both 

1 


2  THE  WORLD  OF  LIFE 

externally  and  internally  he  could  find  no  resemblance  what- 
ever to  his  own  body;  to  crabs  and  winged  insects,  to  land- 
shells  and  sea-shells,  and  ultimately  to  everything  which  by 
moving  and  feeding,  by  growdng  and  dying,  showed  that  it 
was,  like  himself,  alive.  Here,  probably,  he  would  rest  for 
awhile,  and  it  might  require  several  generations  of  incipient 
philosophers  to  extend  the  great  generalisation  of  "  life  "  to 
that  omnipresent  clothing  of  the  earth's  surface  produced  by 
the  infinitely  varied  forms  of  vegetation.  The  more  familiar 
any  phenomenon  is  —  the  more  it  is  absolutely  essential  to 
our  life  and  well-being  —  the  less  attention  we  pay  to  it  and 
the  less  it  seems  to  need  any  special  explanation.  Trees,  shrubs, 
and  herbs,  being  outgrowths  from  the  soil,  being  incapable  of 
any  bodily  motion  and  usually  exhibiting  no  indications  of 
sensation,  might  w^ell  have  been  looked  upon  as  a  necessary 
appendage  of  the  earth,  analogous  to  the  hair  of  mammals  or 
the  feathers  of  birds.  It  was  probably  long  before  their  end- 
less diversity  attracted  much  notice,  except  in  so  far  as  the 
fruits  or  the  roots  were  eatable,  or  the  stems  or  foliage  or  bark 
useful  for  huts  or  clothing ;  wdiile  the  idea  that  there  is  in  them 
any  essential  feature  connecting  them  wdth  animals  and  en- 
titling them  to  be  classed  all  together  as  members  of  the  great 
^vorld  of  life  would  only  arise  at  a  considerably  later  stage 
of  development. 

It  is,  in  fact,  only  in  recent  times  that  the  very  close  resem- 
blance of  plants  and  animals  has  been  generally  recognised. 
The  basis  of  the  structure  of  both  is  the  almost  indistinguish- 
able cell ;  both  grow  from  germs ;  both  have  a  varied  life-period 
from  a  few"  months  to  a  maximum  of  a  few"  hundreds  of  vears : 
both  in  all  their  more  highly  organised  forms,  and  in  many  of 
their  lower  types  also,  are  bisexual ;  both  consist  of  an  immense 
variety  of  distinct  species,  which  can  be  classified  in  the  same 
way  into  higher  and  higher  groups;  the  laws  of  variation, 
heredity,  and  the  struggle  for  existence  apply  equally  to  both, 
and  their  evolution  under  these  laws  has  gone  on  in  a  parallel 
course  from  the  earliest  periods  of  the  geological  record. 


WHAT  LIFE  IS  3 

The  differences  between  plants  and  animals  are,  however, 
equally  prominent  and  fundamental.  The  former  are,  with 
few  exceptions,  permanently  attached  to  the  soil ;  they  absorb 
nourishment  in  the  liquid  or  gaseous  state  only,  and  their  tissues 
are  almost  wholly  built  up  from  inorganic  matter,  while  they 
give  no  clear  indications  of  the  possession  of  sensation  or  vol- 
untary motion.  But  notwithstanding  these  marked  differences, 
both  animals  and  plants  are  at  once  distinguished  from  all  the 
other  forms  of  matter  that  constitute  the  earth  on  which  they 
live,  by  the  crowning  fact  that  they  are  alive;  that  they  grow 
from  minute  germs  into  highly  organised  structures;  that  the 
functions  of  their  several  organs  are  definite  and  highly  varied, 
and  such  as  no  dead  matter  does  or  can  perform ;  that  they  are 
in  a  state  of  constant  internal  flux,  assimilating  new  material 
and  throwing  off  that  which  has  been  used  or  is  hurtful,  so  as 
to  preserve  an  identity  of  form  and  structure  amid  constant 
change.  This  continuous  rebuilding  of  an  ever-changing  highly 
complex  structure,  so  as  to  preserve  identity  of  type  and  at 
the  same  time  a  continuous  individuality  of  each  of  many 
myriads  of  examples  of  that  type,  is  a  characteristic  found 
nowhere  in  the  inorganic  world. 

So  marvellous  and  so  varied  are  the  phenomena  presented 
by  living  things,  so  completely  do  their  powers  transcend  those 
of  all  other  forms  of  matter  subjected  to  mechanical,  physical, 
or  chemical  laws,  that  biologists  have  vainly  endeavoured  to 
find  out  what  is  at  the  bottom  of  their  strange  manifestations, 
and  to  give  precise  definitions,  in  terms  of  physical  science,  of 
what  "life''  really  is.  One  authority  (in  Chambers's  Ency- 
clopaedia) summed  it  up  in  three  w^ords — "Continuity, 
Ehythm,  and  Freedom," —  true,  perhaps,  but  not  explanatory ; 
while  Herbert  Spencer  declared  it  to  be  — "  the  definite  com- 
bination of  heterogeneous  changes,  both  simultaneous  and  suc- 
cessive, in  correspondence  with  external  co-existences  and 
sequences."  This  is  so  technical  and  abstract  as  to  be  unin- 
telligible to  ordinary  readers. 

The   following   attempt   at   a   tolerably   complete   definition 


4  THE  WORLD  OF  LIFE 

appears  to  sum  up  the  main  distinctive  characters  of  living 
things : — 

Life  is  that  'power  which,  primarily  from  air  and  water  and 
the  substances  dissolved  therein,  builds  up  organised  and  highly 
complex  structures  possessing  definite  forms  and  functions: 
these  are  preserved  m  a  continuous  state  of  decay  and  repair  by 
internal  circulation  of  fluids  and  gases;  they  reproduce  their 
like,  go  through  various  phases  of  youth,  maturity,  and  age, 
die,  and  quickly  decompose  into  their  constituent  elements. 
They  thus  form  continuous  series  of  similar  individuals;  and, 
so  long  as  external  conditions  render  their  existence  possible, 
seem  to  possess  a  potential  immortality. 

The  characteristics  here  enumerated  are  those  which  apply 
to  both  plants  and  animals,  and  to  no  other  forms  of  matter 
whatever.  It  is  often  stated  that  crystals  exhibit  the  essential 
features  of  some  of  the  lowest  plants ;  but  it  is  evident  that, 
with  the  exception  of  the  one  item  of  "  definite  form/^  they 
in  no  way  resemble  living  organisms.  There  is  no  doubt,  how- 
ever, that  crystals  do  exhibit  definite  forms,  built  up  by  the 
atoms  or  molecules  of  various  elements  or  compounds  under 
special  conditions.  But  this  takes  us  a  very  small  way  towards 
the  complex  structure  and  organisation  of  living  things. 

There  are  still  people  who  vaguely  believe  that  ^^  stones 
grow,"  or  that  '^  all  matter  is  really  alive,"  or  that,  in  their 
lowest  and  simplest  forms,  the  organic  and  the  inorganic  are 
indistinguishable.  For  these  ideas,  however,  there  is  not  a 
particle  of  scientific  justification.  But  the  belief  that  '^  life  " 
is  a  product  of  matter  acted  upon  by  chemical,  electrical,  or 
other  physical  forces,  is  very  widely  accepted  by  men  of  science 
at  the  present  day,  perhaps  by  a  majority.  It  is,  in  fact,  held 
to  be  the  only  scientific  view,  under  the  name  of  ^'  monism  " ; 
while  the  belief  that  ^^  life  "  is  sui  generis,  that  it  is  due  to 
other  laws  than  those  which  act  upon  dead  or  unorganised 
matter,  that  it  affords  evidence  of  an  indwelling  power  and 
guidance  of  a  special  nature,  is  held  to  be  unscientific  —  to 
be,  in  fact,  an  indication  of  something  akin  to,  if  not  actually 


WHAT  LIFE  IS  5 

constituting,  an  old-fashioned  superstition.  That  such  a  view 
is  not  uncommon  may  be  shown  by  a  few  extracts  from  scien- 
tific writers  of  some  eminence. 

The  well-known  German  biologist  Ernst  Haeckel,  in  a  recent 
work,  makes  the  following  statement : 

"  The  peculiar  phenomenon  of  consciousness  is  not,  as  Du  Bois- 
Eeymond  and  the  dualistic  school  would  have  us  believe,  a  com- 
pletely transcendental  problem ;  it  is,  as  I  showed  thirty-three  years 
ago,  a  physiological  problem,  and,  as  such,  must  be  reduced  to  the 
phenomena  of  physics  and  chemistry  "  (The  Eiddle  of  the  Uni- 
verse, p.  65,  translated  by  Joseph  M'Cabe). 

Again  he  says : 

"  The  two  fundamental  forms  of  substance,  ponderable  matter 
and  ether,  are  not  dead,  and  only  moved  by  extrinsic  force,  but  they 
are  endowed  with  sensation  and  will  (although,  naturally,  of  the 
lowest  grade)  ;  they  experience  an  inclination  for  condensation,  a 
dislike  of  strain;  they  strive  after  the  one  and  struggle  against  the 
other''  (p.  78). 

In  these  two  passages  we  have  a  self-contradiction  in  mean- 
ing if  not  in  actual  words.  In  the  first,  he  reduces  conscious- 
ness to  phenomena  of  physics  and  chemistry ;  in  the  second 
he  declares  that  both  matter  and  ether  possess  sensation  and 
will.  But  in  another  passage  he  says  he  conceives  ^^  the  ele- 
mentary psychic  qualities  of  sensation  and  will  which  may  be 
attributed  to  atoms  to  be  unconscious"  (p.  64). 

It  is  this  quite  unintelligible  theory  of  matter  and  ether 
possessing  sensation  and  will,  being  able  to  strive  and  struggle 
and  yet  be  unconscious,  which  enables  him  to  say: 

"We  hold  with  Goethe  that  matter  cannot  exist  and  be  oper- 
ative without  spirit,  nor  spirit  without  matter.  We  adhere  firmly 
to  the  pure,  unequivocal  monism  of  Spinoza :  Matter,  or  infinitely 
extended  substance,  and  Spirit  (or  Energy),  or  sensitive  and  think- 
ing substance,  are  the  two  fundamental  attributes,  or  principal 
properties,  of  the  all-embracing  essence  of  the  world,  the  universal 
substance"  (p.  8). 


6  THE  WOELD  OF  LIFE 

Here  we  have  yet  another  contradiction  —  that  the  tJiinking 
infinite  substance  is  unconscious!  This  leads  to  his  theory 
of  the  "  cell-soul/'  which  is  the  origin  of  all  consciousness,  hut 
which  is  itself  unconscious.  This  he  reiterates  emphatically. 
He  tells  us  that  at  a  certain  grade  of  organisation  '^  conscious- 
ness has  been  gradually  evolved  from  the  psychic  reflex  activity, 
and  now  conscious  voluntary  action  appears"  (p.  41).  Along 
wdth  these  strange  conceptions,  "vvhich  really  explain  nothing, 
he  propounds  his  "  Law  of  Substance  "  as  the  one  great  foun- 
dation of  the  universe.  This  is  merely  another  name  for 
"  persistence  of  force  "  or  ^'  conservation  of  energ}^,"  yet  at 
the  end  of  the  chapter  expounding  it  he  claims  that,  ''  in  a 
negative  way,  it  rules  out  the  three  central  dogmas  of  meta- 
physics—  God,  freedom,  and  immortality"  (p.  83).  A  little 
further  on  he  again  states  his  position  thus: 

"  The  development  of  the  universe  is  a  monistic  mechanical 
process,  in  which  we  discover  no  aim  or  purpose  whatever;  what 
we  call  design  in  the  organic  world  is  a  special  result  of  biological 
agencies;  neither  in  the  evolution  of  the  heavenly  bodies,  nor  in 
that  of  the  crust  of  the  earth  do  we  find  any  trace  of  a  controlling 
purpose  —  all  is  the  result  of  chance.^' 

Then,  after  discussing  what  is  meant  by  chance,  he  con- 
cludes : 

"  That,  however,  does  not  prevent  us  from  recognising  in  each 
'  chance '  event,  as  we  do  in  the  evolution  of  the  entire  cosmos,  the 
universal  sovereignty  of  nature's  supreme  law,  the  taw  of  sub' 
stance'*   (p.  97). 

Again,  he  defines  his  position  still  more  frankly: 

*'  Atheism  affirms  that  there  are  no  gods  or  goddesses,  assuming 
that  god  means  a  personal,  extra-mundane  entity.  This  ^  godless 
world-system '  substantially  agrees  with  the  monism  or  pantheism 
of  the  modern  scientist.  It  is  only  another  expression  for  it,  em- 
phasising its  negative  aspect,  the  non-existence  of  any  supernatural 
deity"   (p.  103). 


WHAT  LIFE  IS  7 

These  vague  and  often  incomprehensible  assertions  are  inter- 
spersed with  others  equally  unprovable,  and  often  worded  so 
as  to  be  very  offensive  to  religious  minds.  After  having  put 
forth  a  host  of  assertions  as  to  a  possible  future  state,  which 
exhibit  a  deplorable  ignorance  of  the  views  of  many  advanced 
thinkers  in  all  the  Churches,  he  says: 

"  Our  own  ^  human  nature '  which  exalted  itself  into  an  image 
of  God  in  an  anthropistic  illusion,  sinks  to  the  level  of  a  placental 
mammal,  which  has  no  more  value  for  the  universe  at  large  than 
the  ant,  the  fly  of  a  summer's  day,  the  microscopic  infusorium,  or 
the  smallest  bacillus.  Humanity  is  but  a  transitory  phase  of  the 
evolution  of  an  eternal  substance,  a  particular  phenomenal  form  of 
matter  and  energy,  the  true  proportion  of  which  we  soon  perceive 
when  we  set  it  on  the  background  of  infinite  space  and  eternal 
time"    (p.  87). 

The  writings  of  Haeckel,  the  extremely  dogmatic  and  asser- 
tive character  of  which  have  been  illustrated  in  the  preceding 
quotations,  have  had  an  immense  influence  on  many  classes  of 
readers,  who,  when  a  man  becomes  widely  known  as  a  great 
authority  in  any  department  of  science,  accept  him  as  a  safe 
guide  in  any  other  departments  on  which  he  expresses  his 
opinions.  But  the  fact  is  that  he  has  gone  altogether  out  of 
his  own  department  of  biological  knowledge,  and  even  beyond 
the  whole  range  of  physical  science,  when  he  attempts  to  deal 
with  problems  involving  ''  infinity  "  and  ^'  eternity."  He  de- 
clares that  "  matter,"  or  the  material  universe,  is  infinite,  as 
is  the  ''  ether,"  and  that  together  they  fill  infinite  S2:)ace,  and 
that  both  are  ^^  eternal "  and  both  ''  alive."  ^one  of  these 
things  can  possibly  be  hnown,  yet  he  states  them  as  positive 
facts.  The  whole  teaching  of  astronomy  by  the  greatest 
astronomers  to-day  is  that  the  evidence  now  at  our  command 
points  to  the  conclusion  that  our  material  universe  is  finite, 
and  that  we  are  rapidly  approaching  to  a  knowledge  of  its 
extent.  Our  yearly  increasing  acquaintance  with  the  possibil- 
ities of  nature  leads  us  to  the  conclusion  that  in  infinite  space 


8  THE  WORLD  OF  LIFE 

there  lyiay  be  other  universes  besides  ours;  but  if  so,  they  may 
l^ossibly  be  different  from  ours  —  not  of  matter  and  ether  only. 
To  assert  the  contrary,  as  Ilaeckel  does  so  confidently,  is  surely 
not  science,  and  very  bad  philosophy. 

He  further  implies,  and  even  expressly  states,  that  there  is 
no  spirit-world  at  all ;  that  if  life  exists  in  other  worlds  it  must 
be  material,  physical  life;  and  that,  as  all  worlds  move  in 
cycles  of  development,  maturity,  and  destruction,  all  life  must 
go  through  the  same  phases  —  that  this  has  gone  on  from  all 
eternity  past,  and  will  go  on  for  all  eternity  to  come,  with  no 
past  and  no  future  possible,  but  the  continual  rise  of  life  up  to 
a  certain  limited  grade,  which  life  is  always  doomed  to  extinct 
tion.  And  it  is  claimed  that  this  eternal  succession  of  futile 
cycles  of  chance  development  and  certain  extinction  is,  as  an 
interpretation  of  nature,  to  be  preferred  to  any  others ;  and 
especially  to  those  which  recognise  mind  as  superior  to  matter, 
which  see  in  the  development  of  the  human  intellect  the  prom- 
ise of  a  future  life,  and  which  have  in  our  own  day  found  a 
large  mass  of  evidence  justifying  that  belief. 

With  Professor  HaeckeFs  dislike  of  the  dogmas  of  theo- 
logians, and  their  claims  to  absolute  knowledge  of  the  nature 
and  attributes  of  the  inscrutable  mind  that  is  the  power  within 
and  behind  and  around  nature,  many  of  us  have  the  greatest 
sympathy ;  but  we  have  none  with  his  unfounded  dogmatism 
of  combined  negation  and  omniscience,  and  more  especially 
when  this  assumption  of  superior  knowledge  seems  to  be  put 
forward  to  conceal  his  real  ignorance  of  the  nature  of  life 
itself.  He  evades  altogether  any  attempt  to  solve  the  various 
difficult  problems  of  nutrition,  assimilation,  and  growth,  some 
of  which,  in  the  case  of  birds  and  insects,  I  shall  endeavour 
to  set  forth  as  clearly  as  possible  in  the  present  volume.  As 
Professor  Weismann  well  puts  it,  the  causes  and  mechanism 
by  which  it  comes  about  that  the  infinitely  varied  materials 
of  which  organisms  are  built  up  ^'  are  always  in  the  right 
place,  and  develop  into  cells  at  the  right  time,"  are  never 
touched  upon  in  the  various  theories  of  heredity  that  have  been 


WHAT  LIFE  IS  9 

put  forward,  and  least  of  all  in  that  of  Haeckel,  who  comes 
before  us  with  what  he  claims  to  be  a  solution  of  the  Riddle 
of  the  Universe. 

Huxley  on  the  Nature  and  Origin  of  Life 

Although  our  greatest  philosophical  biologist,  the  late  Pro- 
fessor T.  H.  Huxley,  opposed  the  theory  of  a  ''  vital  force  " 
as  strongly  as  Haeckel  himself,  I  am  inclined  to  think  that 
he  did  so  because  it  is  a  mere  verbal  explanation  instead  of 
being  a  fundamental  one.  It  conceals  our  real  ignorance  un- 
der a  special  term.  In  his  Introduction  to  the  Classification 
of  Animals  (1869),  in  his  account  of  the  Rhizopoda  (the 
group  including  the  Amoebse  and  Foraminifera),  he  says: 

"Nor  is  there  any  group  in  the  animal  kingdom  which  more 
admirably  illustrates  a  very  well-founded  doctrine,  and  one  which 
was  often  advocated  by  John  Hunter,  that  life  is  the  cause  and  not 
the  consequence  of  organisation;  for  in  these  lowest  forms  of  ani- 
mal life  there  is  absolutely  nothing  worthy  of  the  name  of  organi- 
sation to  be  discovered  by  the  microscopist,  though  assisted  by  the 
beautiful  instruments  that  are  now  constructed.  .  .  .  It  is 
structureless  and  organless,  and  without  definitely  formed  parts. 
Yet  it  possesses  all  the  essential  properties  and  characters  of  vitality. 
Nay,  more,  it  can  produce  a  shell;  a  structure,  in  many  cases,  of 
extraordinary  complexity  and  most  singular  beauty. 

"  That  this  particle  of  jelly  is  capable  of  guiding  physical  forces 
in  such  a  manner  as  to  give  rise  to  those  exquisite  and  almost 
mathematically-arranged  structures  —  being  itself  structureless 
and  without  permanent  distinction  or  separation  of  parts  —  is 
to  my  mind  a  fact  of  the  profoundest  significance'^    (p.   10). 

This  was  written  only  a  year  after  the  celebrated  lecture 
on  "  The  Physical  Basis  of  Life,"  in  which  Huxley  made 
statements  which  seem  opposed  to  those  above  quoted,  and  which 
certainly  appear  to  be  less  philosophical.  For  example,  he 
says  that  when  carbon,  hydrogen,  oxygen,  and  nitrogen  are 
combined  with  some  other  elements,  they  produce  carbonic  acid, 
water,  and  nitrogenous  salts.     These  compounds  are  all  life- 


10  THE  WORLD  OF  LIFE 

less.  "  But  wlien  they  are  brought  together  under  certain 
conditions  they  give  rise  to  the  still  more  complex  body,  proto- 
plasm, and  this  protoplasm  exhibits  the  phenomena  of  life  " 
(p.  52).  Then  follows  an  exposition  of  the  well-known  argu- 
ment as  to  water  and  crystals  being  produced  by  the  "  proper- 
ties "  of  their  constituent  elements,  with  this  conclusion : 

"  Is  the  case  any  way  changed  when  carbonic  acid,  water,  and 
nitrogenous  salts  disappear,  and  in  their  place,  under  the  influence 
of  pre-existing  living  protoplasm,  an  equivalent  weight  of  the 
matter  of  life  makes  its  appearance?"   (p.  53). 

But  here  we  have  the  words  I  have  italicised  introduced 
which  were  not  in  the  previous  staj:ement;  and  these  are  of 
fundamental  importance  considering  the  tremendous  conclu- 
sion he  goes  on  to  draw  from  them  — "  that  the  thoughts  to 
which  I  am  now  giving  utterance  are  the  exj)ression  of  molec- 
ular changes  in  that  matter  of  life  which  is  the  source  of  our 
other  vital  phenomena."  At  the  end  of  the  lecture  he  says 
that  "  it  is  of  little  moment  whether  we  express  the  phenomena 
of  matter  in  terms  of  spirit,  or  the  phenomena  of  spirit  in 
terms  of  matter  —  each  statement  has  a  certain  relative  truth." 
But  he  thinks  that  in  matters  of  science  the  materialistic  ter- 
minology is  in  every  way  to  be  preferred. 

This  is  vague  and  unsatisfactory.  It  is  not  a  mere  question 
of  terminology ;  but  his  statement  that  "  thought  is  the  expres- 
sion of  molecular  change  in  protoplasm "  is  a  mere  begging 
of  the  whole  question,  both  because  it  is  absolutely  unproved, 
and  is  also  inconsistent  with  that  later  and  clearer  statement 
that  "  life  is  the  cause  of  organisation  " ;  but,  if  so,  life  must 
be  antecedent  to  organisation,  and  can  only  be  conceived  as 
indissolubly  connected  with  spirit  and  with  thought,  and  with 
the  cause  of  the  directive  energy  everyw^here  manifested  in  the 
growth  of  living  things. 

In  the  present  volume  I  am  endeavouring  to  arrive  at  a 
juster  conception  of  the  mystery  of  the  Life- World  than  that 
of  Professor  Haeckel,  and  bv  a  verv  different  method.     I  shall 


WHAT  LIFE  IS  11 

endeavour  to  give  a  kind  of  bird's-eye  sketch  of  the  great  life- 
drama  in  many  of  its  broader  and  less-known  phases,  showing 
how  they  all  form  parts  of  the  grand  system  of  evolution, 
through  adaptation  to  continuous  changes  in  the  outer  world. 
I  shall  also  endeavour  to  penetrate  into  some  of  the  less  trodden 
paths  of  nature-study,  in  order  to  exhibit  the  many  indications 
that  exist  of  the  preparation  of  the  Earth  for  Man  from  the 
remotest  eons  of  geological  time. 


CHAPTER    II 

SPECIES  THEIK    NUMBEKS,     VAKIETY,    AND    DISTRIBUTION 

When  we  begin  to  inquire  into  the  main  features,  the  mode 
of  development,  the  past  history,  and  the  probable  origin  of 
the  great  World  of  Life  of  which  we  form  a  part,  which 
encloses  us  in  its  countless  ramifications,  and  upon  whose  pres- 
ence in  ample  quantity  we  depend  for  our  daily  food  and 
continued  existence,  we  have  perpetually  to  discuss  and  to  deal 
with  those  entities  technically  kno^vn  as  species,  but  which  are 
ordinarily  referred  to  as  soi'ts  or  kinds  of  plants  and  animals. 
When  we  ask  how  many  hinds  of  deer  or  of  thiTishes,  of  trout 
or  of  butterflies,  inhabit  Britain,  w^e  mean  exactly  the  same 
thing  as  the  biologist  means  by  species,  though  we  may  not  be 
able  to  define  what  we  mean  so  precisely  as  he  does. 

Many  people  imagine,  however,  that  Darwin's  theory  proves 
that  there  are  no  such  things  as  species ;  but  this  is  a  complete 
misconception,  though  some  biologists  use  language  which 
seems  to  support  it.  To  myself,  and  I  believe  to  most  natural- 
ists, species  are  quite  as  real  and  quite  as  important  as  when 
they  were  held  to  be  special  creations.  They  are  even  more 
important,  because  they  constitute  the  only  definite,  easily  rec- 
ogTiised,  and  easily  defined  entities  which  form  the  starting- 
point  in  all  rational  study  of  the  vast  complex  of  living  things. 
They  are  now  known  to  be  not  fixed  and  immutable  as  for- 
merly supposed;  yet  the  great  mass  of  them  are  stable  within 
very  narrow  limits,  w^hile  their  changes  of  form  are  so  slow, 
that  it  is  only  now,  after  fifty  years  of  continuous  search  by 
countless  acute  observers,  that  we  have  been  able  to  discover 
a  very  few  cases  in  which  a  real  change  —  the  actual  produc- 
tion of  new  species  —  appears  to  be  going  on  before  our  eyes. 
The  reader  may  therefore  rest  assured  that  there  is  no  mystery 

1^ 


DISTRIBUTIO'N^  OF  SPECIES  13 

in  the  word  species,  but  that  he  may  take  it  as  meaning  the 
same  as  kind,  in  regard  to  animals  and  plants  in  a  state  of 
nature,  and  that  he  will  have  no  difficulty  in  following  the 
various  discussions  and  expositions  in  which  this  term  is  nec- 
essarily so  prominent.  The  reason  why  species  is  the  better 
term  is  because  hind  is  used  in  two  distinct  senses  —  that  of 
species  when  we  speak  of  kinds  of  deer,  of  squirrels,  or  of 
thrushes,  but  also  that  of  a  genus  or  a  family  when  we 
speak  of  the  deer,  squirrel,  or  thrush  kind,  as  meaning  the 
whole  group  of  these  animals.  If  we  used  the  word  tribe 
instead  of  hind  in  this  latter  sense,  all  ambiguity  would  be 
avoided. 

Eew  persons  who  have  not  studied  some  branch  of  natural 
history  have  any  idea  of  the  vast  extent,  the  infinite  variety, 
the  omnipresence  and  the  intermingling  of  the  varied  species 
of  animals  and  plants,  and  still  less  of  their  wonderful  co-adap- 
tation and  interdependence.  It  is  these  very  characteristics 
that  are  least  dwelt  upon  in  books  on  natural  history,  and  they 
are  largely  overlooked  even  in  works  on  evolution.  Yet  they 
form  the  very  basis  of  the  phenomena  to  be  explained,  and 
furnish  examples  of  development  through  survival  of  the  fittest, 
on  a  larger  scale  and  often  of  easier  comprehension  than  the 
special  cases  most  frequently  adduced.  It  is  this  ground-work 
of  the  whole  subject  that  we  will  now  proceed  to  consider. 

The  Distribution  of  Local  and  ^yorld  Species 

The  first  important  group  of  facts  which  we  have  to  con- 
sider is  that  which  relates  to  the  number  of  existing  species 
of  the  tw^o  great  divisions  of  life,  plants  and  animals,  and  their 
mode  of  distribution  over  the  earth's  surface. 

Every  one  who  begins  to  study  and  collect  any  gToup  of 
animals  or  plants  is  at  once  struck  by  the  fact  that  certain 
fields,  or  woods,  or  hills  are  inhabited  by  species  which  he  can 
find  nowhere  else ;  and  further,  that,  whereas  some  kinds  are 
very  common  and  are  to  be  found  almost  everywliere,  others 
are  scarce  and  only  occur  in  small  numbers  even  in  the  places 


14  THE  WORLD  OF  LIFE 

where  alone  they  are  usually  to  be  found.  These  peculiarities 
are  most  strongly  marked  in  the  case  of  plants,  and  in  a  less 
degree  among  insects  and  land-shells;  and  in  the  former  group 
they  are  easily  seen  to  depend  mainly  on  such  obvious  peculiari- 
ties as  soil  and  moisture,  exposure  to  sun  or  wind,  the  pres- 
ence or  absence  of  woods,  streams,  or  mountains. 

But  besides  these  inorganic  causes  —  soil,  climate,  aspect, 
etc. —  which  seem  primarily  to  determine  the  distribution  of 
plants,  and,  through  them,  of  many  animals,  there  are  other 
and  often  more  powerful  causes  in  the  organic  environment 
which  acts  in  a  variety  of  ways.  Thus,  it  has  been  noticed 
that  over  fields  or  heaths  where  cattle  and  horses  have  free 
access  seedling  trees  and  shrubs  are  so  constantly  eaten  down 
that  none  ever  grow  to  maturity,  even  although  there  may  be 
plenty  of  trees  and  woods  around.  But  if  a  portion  of  this 
very  same  land  is  enclosed  and  all  herbivorous  quadrupeds 
excluded,  it  very  quickly  becomes  covered  with  a  dense  vege- 
tation of  trees  and  shrubs.  Again,  it  has  been  noticed  that 
on  turfy  banks  constantly  cropped  by  sheep  a  very  large  variety 
of  dwarf  plants  are  to  be  found.  But  if  these  animals  are 
kept  out  and  the  vegetation  allowed  to  grow*  freely,  many  of 
the  dwarfer  and  more  delicate  plants  disappear  owing  to  the 
rapid  growth  of  grasses,  sedges,  or  shrubby  plants,  which,  by 
keeping  off  the  sun  and  air  and  exhausting  the  soil,  prevent 
the  former  kinds  from  producing  seed,  so  that  in  a  few  years 
they  die  out  and  the  vegetation  becomes  more  uniform. 

A  modified  form  of  the  same  general  law  is  seen  when  any 
ground  is  cleared  of  all  vegetation,  perhaps  cultivated  for  a 
year  or  two,  and  then  left  fallow.  A  large  crop  of  weeds 
then  grows  up  (the  seeds  of  which,  must  have  beeoi  brought 
by  the  wind  or  by  birds,  or  have  lain  dormant  in  the  ground)  ; 
but  in  the  second  and  third  years  these  change  their  propor- 
tions, some  disappear,  while  a  few  new  ones  arrive,  and  this 
change  goes  on  till  a  stable  form  of  vegetation  is  formed,  often 
very  different  from  that  of  the  surrounding  country.  Such 
changes  as  these  have  been  observed  by  local  botanists  on  rail- 


DISTRIBUTION  OF  SPECIES  15 

way  banks,  of  which  I  have  given  several  examples  in  my 
Island  Life  (p.  513,  footnote).  All  these  phenomena,  and 
many  others  which  will  be  referred  to  later,  are  manifestly 
due  to  that  "  struggle  for  existence  "  which  is  one  of  the  great 
factors  of  evolution  through  "  survival  of  the  fittest." 

A  Lincolnshire  clergyman  (Rev.  E.  Adrian  Woodruff e-Pea- 
cock  of  Cadney)  has  long  studied  the  distribution  of  plants  in 
a  very  minute  and  interesting  manner,  more  especially  in  his 
own  parish,  but  very  extensively  over  the  whole  county.  His 
more  exact  method  is  to  divide  up  a  field  into  squares  of  about 
16  feet  each  way  with  pegs,  and  then  to  note  on  special  forms 
or  note-books  (1)  a  list  of  the  species  found  in  each  square, 
and  (2)  the  frequency  (or  proportion)  of  the  occurrence  of 
each  species.  From  these  the  frequency  over  the  whole  field 
can  be  estimated,  and  the  botanical  peculiarities  of  various 
fields  very  accurately  determined.  By  comparing  the  detailed 
flora  of  each  field  with  its  surface-geology,  aspect,  altitude, 
degree  of  moisture  or  aridity,  etc.,  a  very  accurate  conclusion 
as  to  the  likes  and  dislikes  of  particular  plants  may  be  arrived 
at. 

As  an  example  of  the  detailed  treatment  of  a  rather  uncom- 
mon yet  widely  distributed  plant,  he  has  sent  me  a  copy  of  his 
paper  on  the  Black  Horehound  (Ballota  nigra),  sl  species  not 
uncommon  over  much  of  Central  Europe,  but  scattered  over 
Central  and  Southern  Britain  only  in  a  few  favourable  locali- 
ties. In  Lincolnshire  it  is  found  all  over  the  county  in  suitable 
spots,  but  prefers  a  warm,  open,  and  limy  soil,  as  shown  by 
150  records  giving  notes  of  its  occurrence.  The  general  results 
of  the  inquiry  are  thus  given: 

"AVhen  the  sheets  of  notes  are  analysed  the  following  points 
come  out.  It  is  a  hedge  and  ditch-side  species,  but  it  seems  to 
prefer  a  bank  to  the  flat  in  the  proportion  of  10  to  1 ;  the  sunny 
bank  to  the  shady  side  of  a  road  running  east  and  west  in  nearly 
the  same  proportion.  On  sandy  soils  it  seems  to  get  away  from 
the  villages  to  a  greater  distance  than  on  clays,  but  perhaps  the 
rabbit  may  explain  this.     It  extends  from  Cadney  village  along 


16  THE  WORLD  OF  LIFE 

hedge  and  ditch  banks  on  roadsides  as  far  as  the  Sandy  Glacial 
Gravel  extends  in  any  direction.  It  is  found  in  bushy  ground, 
in  old  quarries  and  gravel  pits,  and  on  the  decaying  mud-capping 
of  limestone  walls.  It  is  exterminated  by  stock  in  pasture,  unless 
it  is  protected  by  the  stinging-nettle  or  by  the  fouling  of  the 
ground  by  rabbits.  It  is  apparently  never  found  in  meadows.  It 
is  even  sometimes  eaten  by  cows,  when  the  much-loved  Lamium 
album  (the  white  dead-nettle)  is  left  untouched;  but  it  would 
seeem  to  be  taken  as  a  corrective  or  relish  rather  than  as  food. 
It  is  found  so  rarely  in  the  open  that  it  would  almost  appear 
to  be  a  shade  species  of  bushy  ground. 

*' To  sum  up,  Ballota  nigra  can  only  survive  (in  Lincolnshire) 
when  unconsciously  protected  by  man;  for  its  natural  require- 
ments, a  bushy,  open,  limy,  lightly  stocked  soil  is  practically  not 
to  be  found.^' 

This  careful  study  of  a  single  species  of  plant  gives  us  an 
excellent  picture  of  the  struggle  for  existence  on  the  outer 
limit  of  the  range  of  a  species,  where  it  first  becomes  rare, 
and,  when  the  conditions  become  a  little  less  favourable,  ceases 
to  exist.  How  this  struggle  affects  the  flora  of  limited  areas 
under  slightly  different  conditions  is  shown  by  the  same 
writer's  comparison  of  meadow  and  pasture. 

Tw^o  fields  of  each  were  chosen  in  the  same  parish  and  with 
the  same  subsoil  (Sandy  Glacial  Gravel)  so  as  to  afford  fair 
examples  of  each.  With  the  one  exception  of  the  mode  of 
cultivation  they  were  as  alike  as  possible.  Both  had  at  some 
remote  period  been  ploughed,  as  shown  by  faint  ridges,  but 
no  one  living  or  their  immediate  predecessors  could  remember 
them  in  any  different  condition  from  the  present  one.  The 
four  fields  (29  acres  together)  contained  in  all  78  species  of 
plants ;  but  only  46  of  these  were  found  in  both  pasture  and 
meadow.  The  number  of  species  in  each  was  nearly  the  same 
—  60  in  the  meadows,  64  in  the  pastures ;  14  species  being 
found  only  in  the  meadows  and  18  in  the  pastures.  Broadly 
speaking,  therefore,  one-fifth  of  all  the  species  growing  on  these 
29   acres  became   restricted   to  well-defined   portions   of  them 


disteibutio:n^  of  species  17 

according  as  these  portions  were  grazed  by  farm  stock  or  reg- 
ularly mown  for  hay. 

Again,  Mr.  Woodruff e-Peacock  states,  that  the  assemblage 
of  plants  that  form  pasture-lands  not  only  varies  with  every 
change  of  soil  and  climate,  but  also  with  any  change  of  the 
animals  that  feed  upon  them ;  so  that  any  one  experienced 
and  observant  can  tell,  by  the  presence  of  certain  plants  and 
the  absence  of  others,  whether  horses,  cattle,  or  sheep  have  been 
the  exclusive  or  predominant  animals  that  have  grazed  upon  it. 

Another  point  of  some  importance  is  the  greater  stability 
in  the  flora  of  meadow  as  compared  with  that  of  pasture  land. 
In  the  former  only  one  plant  was  an  accidental  straggler,  while 
in  the  latter  there  were  12,  or  two-thirds  of  the  peculiar  spe- 
cies. These  are  mostly  rare,  and  are  very  often  not  truly  Brit- 
ish plants,  so  that  they  cannot  be  considered  as  permanent 
pasture  plants.  The  more  stable  meadow  flora  is  no  doubt 
largely  due  to  the  fact  that  few  of  the  late-flowering  plants 
are  allowed  to  produce  seed,  and  though  seed  may  be  often 
introduced  by  birds  or  the  wind,  many  of  these  species  soon 
die  out.  It  thus  appears  that  though  pastures  are  actually 
richer  in  species  than  meadows,  yet  the  latter  have  a  more 
permanent  character,  as  almost  all  those  peculiar  to  pastures 
are  comparatively  rare  and  therefore  very  liable  to  disappear 
through  very  slight  changes  of  conditions. 

These  various  facts,  and  many  others  which  cannot  be  here 
given,  serve  to  show  us  how  very  delicate  are  the  mutual  rela- 
tions and  adjustments  of  plants  to  their  total  environment. 
In  proportion  as  that  environment  is  subject  to  change  of  any 
kind,  some  rare  species  die  out,  while  others  become  diminished 
in  numbers.  And  what  takes  place  in  single  fields  or  other 
small  areas,  when  closely  studied,  must  certainly  occur  on  a 
much  grander  scale  over  the  whole  earth,  and  especially  in 
those  countries  and  periods  when  great  changes  of  climate  or 
of  physical  geography  are  taking  place.  These  detailed  studies 
of  "  Meadow  and  Pasture  Analysis  " —  as  their  author  terms 
them  —  thus  demonstrate  on  a  very  small  scale  that  "  struggle 


18  THE  WOELD  OF  LIFE 

for  existence  "  which,  as  we  shall  see  further  on,  is  always 
present,  acts  in  an  almost  infinite  number  of  ways,  and  is  one 
of  the  most  important  factors  in  the  developmental  changes 
of  the  World  of  Life.  We  will  now  proceed  to  give  some  of 
the  numerical  facts  of  plant  distribution,  in  various  areas  small 
and  large,  as  well  as  over  the  whole  earth;  but  it  will  be  ad- 
visable first  to  give  a  brief  account  of  the  way  in  which  this 
is  usually  dealt  with  by  botanists. 

Four  years  before  the  appearance  of  the  Origin  of  Species 
the  great  Swiss  botanist,  Alphonse  De  Candolle,  published  one 
of  the  most  remarkable  and  interesting  botanical  works  in 
existence,  his  GeogTaphie  botanique  raisonnee,  in  two  thick  vol- 
umes. He  not  only  brought  together  all  the  then  available 
facts  as  to  plant  distribution  in  every  part  of  the  world,  studied 
them  from  almost  every  point  of  view,  and  grouped  them  in 
relation  to  every  known  agency  that  might  be  supposed  to  influ- 
ence their  distribution,  but  at  every  step  he  most  carefully 
and  ingeniously  discussed  the  problems  involved,  often  of  a 
very  intricate  nature,  with  a  view  to  arriving  at  a  more  or  less 
complete  explanation. 

It  is  impossible  here  to  give  any  adequate  notion  of  this 
great  work,  but  a  few  of  the  chief  subjects  treated  may  be 
mentioned.  The  effects  of  temperature  and  of  light  upon  the 
growth  and  vitality  of  plants  are  first  examined,  and  some 
very  interesting  conclusions  are  reached,  among  others  the  great 
importance  of  the  time  during  which  any  particular  degree 
of  heat  continues.  This  discussion  occupies  the  first  three 
chapters.  Sixteen  long  chapters  then  deal  with  "  Botanical 
Geography,"  in  which  all  the  geographical  conditions  that  affect 
the  distribution  of  plants  are  elaborately  discussed,  such  as  alti- 
tude, latitude,  aspect,  humidity,  geological  and  mineralogical 
causes,  both  in  their  direct  and  indirect  action,  and  as  apply- 
ing to  cultivated  as  well  as  ^vild  plants.  The  areas  occupied 
by  species,  both  as  regards  size  and  shape,  are  then  discussed, 
and  the  causes  that  lead  to  their  variations  investigated.  He 
then  shows  what  are  the  actual  areas  in  various  parts  of  the 


DISTRIBUTION  OF  SPECIES  19 

world,  and  under  various  geographical  conditions,  and  thus 
arrives  at  the  causes  of  great  extension  of  certain  species  from 
Vilest  to  east  in  the  north  temperate  zone,  or  along  sea-shores 
or  river-banks  in  the  tropics ;  while  the  normal  area  is  consid- 
ered to  be  '^  massive  "  rather  than  elongated. 

Coming  then  to  detailed  facts,  he  shows  that  about  200 
species  (out  of  the  total  then  known  of  about  120,000)  have 
areas  equal  to  one-third  or  more  of  the  entire  land  surface  of 
tlie  globe.  Further,  in  certain  Families  (usually  called  ^Nat- 
ural  Orders)  there  are  plants  which  range  from  the  Arctic 
regions  to  the  southern  extremity  of  the  great  continents. 
Among  the  former  are  our  common  Marsh  Marigold  (Caltha 
palustris)  and  Common  Sundew  (Drosera  rotund i folia),  which 
are  found  in  all  Northern  Europe,  Asia,  and  America ;  while 
our  common  Sowthistle  (Sonchus  oleraceus)  is  found  scattered 
over  the  whole  globe,  tropical  as  well  as  temperate,  and  is  per- 
haps the  nearest  of  any  known  plant  to  being  truly  cosmopol- 
itan. 

By  a  laborious  comparison  the  author  arrives  at  the  con- 
clusion that  the  average  area  occupied  by  the  species  of  flower- 
ing plants  is  rroth  part  of  the  whole  land  surface  of  the  globe. 
But  the  area  varies  enormously  in  different  parts  of  the  world. 
Thus,  in  the  wdiole  Russian  Empire,  species  have  a  mean  area 
of  irVth  the  land  surface,  owing  to  the  fact  that  so  many  range 
east  and  west  over  a  large  part  of  Europe  and  Xorth  Asia ; 
while  in  South  Africa  the  mean  range  is  only  W&oth  of  that 
surface,  which  expresses  the  fact  of  the  extreme  richness  of 
the  latter  flora,  many  of  the  species  composing  w^hich  have 
extremely  restricted  ranges.  He  also  reaches  the  eonclusion 
that  in  passing  from  the  pole  to  the  equator  the  mean  areas 
of  the  species  become  smaller.  A  few  examples  of  very  lim- 
ited areas  are  the  following :  —  Several  species  of  heaths  are 
found  only  on  Table  Mountain,  Cape  of  Good  Hope;  Cam- 
immda  isopliylJa  grows  only  on  one  promontory  of  the  coast 
of  Genoa;  the  beautiful  Alpine  Gromwell  (Lithospermum 
Gastoni),  on  one  cliff  in  the  Pyrenees;  Wulfenia  Carintliiaca, 


20 


THE  WORLD  OF  LIFE 


on  one  mountain  slope  in  Carintliia ;  Primula  imperialis,  on 
the  summit  of  Mount  Pangerago  in  Java,  and  many  others. 

In  order  to  compare  the  plants  of  different  parts  of  the  world 
in  their  various  relations,  De  Candolle  divides  the  whole  land 
surface  into  fifty  botanical  regions,  each  distingTiished  by  the 
possession  of  a  considerable  proportion  of  peculiar  species  of 
plants.  These  regions  are  of  greatly  varying  extent,  from  Xo. 
18,  comprising  the  whole  of  Xorthern  Asia,  to  Xo.  10,  limited 
to  the  small  island  of  Tristan  d'Acunha  in  the  South  Atlantic. 

The  list  is  as  follows :  — 


A.  De  Candolle's  Botaxical  Regions 


1.  Arctic  zone. 

2.  Europe,  temperate. 

3.  Mediterranean. 

4.  Azores,  Madeira,  Canaries. 

5.  Sahara,   Cape  Verde  Islands. 

6.  Guinea  N.,  Soudan. 

7.  "        S.,   Congo,   Benguela. 

8.  Island  of   St.   Helena. 
0.  South  Africa. 

10.  Tristan   d'Acunha. 

11.  Islands  of  Kerguelen,   St.   Paul, 

etc. 

12.  Madagascar,   etc. 

13.  Mozambique,   Zanzibar. 

14.  Abyssinia  to  Egypt. 

15.  Persia,  Euphrates. 

16.  Caucasus,  Armenia. 

17.  Tartary  east  of  Caspian. 

18.  Siberia,    Ural    to    Kamschatka, 

Lake  Aral. 

19.  Asia  Central. 

20.  Afghanistan  to  Indus. 

21.  Nepal  to  Bhutan. 

22.  China,   Japan. 

23.  Philippines. 

24.  Siam,   Cochin  China. 


25.  Burma  and  Assam. 

26.  Bengal,  Ganges. 

27.  Peninsular  India,  Ceylon. 

28.  Malacca,  N.  Ireland. 

29.  Australia,   New   Zealand. 

30.  Fiji  to  Marquesas. 

31.  Mariannes,  Carolines. 

32.  Sandwich  Islands. 

33.  N.W.  America. 

34.  Canada  and  United  States. 

35.  Texas,   California,  Mexico. 

36.  West   India    Islands. 

37.  Venezuela. 

38.  Colombia. 

39.  Peru. 

40.  Galapagos. 

41.  Bolivia  and   Andes. 

42.  Guayanas. 

43.  Amazonia. 

44.  Brazil    N.E. 

45.  ""        W.,  Paraguay. 

46.  "        S.E. 

47.  Uruguay,  La  Plata. 

48.  Chile,  Juan  Fernandez. 

49.  Patagonia,    Falkland    Islands. 

50.  The   Antarctic  Archipelago. 


By  an  extensive  comparison  of  floras  all  over  the  world  it 
is  found  that  less  than  Ave  per  cent,  of  the  total  of  the  kno^vn 
species  are  found  in  more  than  two  of  these  regions.     Fam- 


DISTRIBUTION  OF  SPECIES  21 

ilies  which  have  very  few  annual  species  show  a  still  smaller 
percentage  (three  per  cent)  ;  while  those  whose  species  are  mostly 
trees  or  shrubs  have  less  than  two  per  cent  which  extend  to 
more  than  two  regions. 

He  also  finds  that  those  with  fleshy  fruits  have  a  wider  dis- 
persal than  those  with  dry  fruits,  and  those  with  very  small 
seeds,  wider  than  those  with  larger  seeds.  Eighteen  species 
only  are  found  to  be  spread  over  half  the  land  surface  of  the 
globe.  There  are  no  trees  or  shrubs  among  these;  grasses  are 
most  abundant  among  them ;  and  composites  —  the  daisy  and 
aster  family  —  the  least !  This  last  conclusion  seems  very 
strange  in  view  of  the  fact  that  this  family  has  its  seeds  so 
frequently  provided  with  special  means  of  dispersal,  either  by 
the  wind  or  by  animals.  But  he  also  points  out,  what  is  now 
well  known  to  botanists,  that  the  species  of  Compositse  are  not 
usually  very  widely  spread ;  and  also  that  several  other  natural 
orders  in  which  the  seeds  are  usually  winged  for  wind-dispersal 
are  not  more  widely  distributed  than  those  whose  seeds  are 
not  winged.  These  facts  certainly  prove  that  the  dispersal  of 
seeds  by  wind  or  by  birds  has  been  brought  about  for  the  pur- 
pose of  securing  ample  means  of  reproduction  Avithin  the  area 
to  which  the  whole  plant  has  become  specially  adapted,  not 
to  facilitate  its  transmission  to  distant  lands  or  islands  which, 
only  in  a  very  few  cases,  would  be  suited  for  its  growth  and 
full  development.  Very  extensive  dispersal  must,  therefore, 
in  most  cases  be  looked  upon  as  an  adventitious  result  of  gen- 
eral  adaptation  to  the   conditions   in   which   a   species   exists. 

De  Candolle's  work  also  treats  very  fully  the  subject  of  the 
comparative  preponderance  of  the  various  natural  orders  of 
plants  in  different  regions  or  countries.  This  mode  of  study- 
ing plant-distribution  was  introduced  by  our  greatest  English 
botanist,  Robert  Brown,  and  it  is  that  most  generally  used  by 
modern  botanical  writers  on  distribution.  It  consists  in  the 
characterisation  of  the  vegetation  of  each  region  or  district  by 
the  proportionate  abundance  in  species  belonging  to  the  dif- 
ferent natural  orders. 


22  THE  WOKLD  OF  LIFE 

This  is  used  in  many  different  ways.  In  one  the  minimum 
number  of  orders  whose  species  added  together  form  one-half 
of  the  whole  flora  are  given.  Thus,  it  was  found  that  in  the 
Province  of  Bahia  (Brazil)  the  11  largest  natural  orders  com- 
prise half  the  whole  number  of  species.  In  British  Guiana 
12  orders  are  required,  and  in  British  India  17.  Coming  to 
temperate  regions,  in  Japan  there  are  16,  in  Europe  10,  in 
Sweden  9,  in  Iceland  and  in  Central  Spain  8.  The  general 
result  seems  to  be  that  those  regions  which  are  very  rich  in  their 
total  number  of  plants  require  a  larger  number  of  their  pre- 
ponderant orders  to  make  up  half  the  total  flora ;  which  implies 
that  they  have  a  larger  proportion  of  orders  which  are  approxi- 
mately equal  in  number  of  species. 

Another  mode  of  comparison  is  to  give  the  names  of  the 
first  three  or  four,  or  even  ten  or  twelve,  of  the  orders  which 
have  the  greatest  number  of  species.  It  is  found,  for  example, 
that  in  equatorial  regions  LeguminossB  usually  come  first, 
though  sometimes  Orchids  are  most  abundant ;  in  temperate 
regions  the  Composites  or  the  Grasses;  and  in  the  Arctic, 
Grasses,  followed  by  Crucifera?  and  Saxifrages.  A  few  of  the 
tables  constructed  by  De  Candolle  are  given  as  examples. 

British  Guiaxa    ( Scliomburgh ) 

3254  species 

Leguminosae 469  species 

Orchidese 214        " 

Rubiacege   176        " 

Melastomaceae  126        " 

The  Andes  of  New  Grenada  (Humboldt) 

1041  species 

Composite   86  species 

Leguminosae 65        "    ' 

Rubiacese    49        " 

Graminese 42        " 

Orchidese    .it,,. •  41        " 


DISTKIBUTION  OF  SPECIES 


23 


Australia  and  Tasmania   (R.  Brown) 

4200  species 

Legiiminosse 
Euphorbiacese 
Compositae 
Orchidese 


Cyperaceae 
Giaminese 
Myrtaceaj 
Proteacese 


Iceland. 

1.  Cyperaceae    47 

2.  Graminese     45 

3.  Compositae   24 

4.  Caryophylleae     23 

5.  Cruciferae 21 

6.  Amentaceae    20 


402  species 

7.  Saxifrageae     15 

8.  Rosaceae    15 

9.  Ericaceae     12 

10.  Juncaceae    12 

11.  Ranunculaceae   11 

12.  Polygoneae    11 


As  a  short  general  conclusion  De  Candolle  says: 


The  Leguminosae 
The  Composites   , 
The  Grasses   .    . 


.    .   dislike  cold. 
,    .    dislike  cold  and  wet. 
dislike  drought. 


Other  examples  will  be  given  when  discussing  the  compara- 
tive relations  of  the  various  temperate  and  tropical  floras  of 
the  world. 


CHAPTER    III 

THE  NUMEEICAL  DISTRIBUTION  OF  BRITISH   PLANTS  I  TEMPERATE 

FLORAS    COMPARED 

Proceeding  from  the  more  to  tlie  less  familiar  regions  we 
will  be^rin  witli  a  few  of  the  facts  as  to  the  flora  of  our  own 
country.  Partly  owing  to  its  insular  character,  and  also  be- 
cause it  has  few  lofty  mountains  or  extensive  forests,  the  num- 
ber of  species  of  flowering  plants  is  somewhat  (but  not  much) 
below  that  of  most  continental  countries  of  equal  area.  It  con- 
tains about  1800  species,  as  a  rough  mean  between  the  estimates 
of  dift'erent  botanists.^  It  may  seem  curious  that  there  should 
be  any  such  difference  of  opinion,  but  one  of  the  facts  that 
have  alwa^^s  been  adduced  as  showing  that  species  are  not  fixed 
and  immutable  entities  is  the  frequent  occurrence  of  varieties, 
which  are  sometimes  so  peculiar  and  so  apparently  constant 
that  they  are  treated  by  some  botanists  as  distinct  species,  by 
others  as  sub-species,  and  by  others  again  as  forms  or  varieties 
only.  These  modifications  of  a  species  are  usually  confined  to 
a  more  limited  area  than  the  species  itself,  and  are  occasionally 
connected  with  each  other  or  with  the  parent  species  by  inter- 
mediate forms.  Again,  when  these  varieties  are  cultivated, 
and  esjDecially  when  a  large  number  of  plants  are  raised  from 
their  seeds,  they  are  apt  to  revert  partially  or  wholly  to  the 
parent  form.  Another  source  of  difference  of  opinion  among 
botanists  is,  as  to  the  treatment  of  those  plants,  found  usually 
near  human  habitations,  which  are  supposed  to  have  been  orig- 
inally introduced,  either  purposely  or  accidentally,  from  foreign 
coimtrios.      Such   are  the  wild  Larks])ur  and  Monkshood,  the 

1  In  all  the  tables  and  comparisons  of  "  Ploras  "  in  this  work,  unless 
where  ferns  are  specially  noted,  flowering  plants  only  are  intended,  even 
when  the  term  '*  plants  "  is  used. 

24 


TEMPERATE  FLORAS 


25 


Red  Valerian,  the  Balm,  the  Martagon  Lily,  and  many  others. 
This  explanation  is  necessary  in  order  to  avoid  any  supposition 
of  positive  error  when  the  figures  here  given  do  not  agree 
with  those  of  anv  of  the  text-books  or  local  floras. 

xJ 

The  chief  diiferences  arise,  however,  from  the  increased 
study  of  certain  difficult  groups  leading  to  the  separation  of 
large  numbers  of  slightly  differing  forms,  that  hardly  any 
one  but  an  expert  can  distinguish,  as  distinct  species.  The 
most  important  of  these  are  the  Brambles  (the  genus  Rubus) 
and  the  Ilawkweeds  (the  genus  Hieracium).  During  the  last 
thirty  years  the  numbers  of  these  have  more  than  doubled, 
according  to  the  standard  authority  for  British  botanists  — 
The  London  Catalogue  of  British  Plants.  The  numbers  in 
an  early  and  late  edition  are  as  follows :  — 


Genus. 

7th    Ed.,    1877. 

lOth  Ed.,    1908. 

Rubus  

54  species 
48 

1 

1 

116  species 
133        " 

Hieracium    

Euphrasia    

15 

Rhinanthus   

8        " 

In  the  last  two  cases  two  well-known  plants  —  the  little 
"  eyebright  "  of  our  turfy  banks,  and  the  ''  yellow  rattle  "  of 
peaty  meadows,  which  have  been  each  considered  to  form  a 
single  species  from  the  time  of  Linnseus  to  that  of  Bentham 
and  Hooker  —  are  now  subdivided  into  a  number  of  distinct 
species,  each  claimed  to  be  well  recognisable  and  constant. 
With  such  rapid  changes  in  the  estimate  of  species  in  so 
well-known  a  flora  as  our  own  it  may  be  thought  that  the 
number  of  species  in  foreign  countries  is  even  more  uncertain. 
This,  however,  is  by  no  means  the  case,  as  tlio  great 
majority  of  the  species  of  plants  a^  well  as  of  animals;  offer 
little  difficulty,  and  present  few  fixed  varieties  (though 
abundance  of  variation),  so  that  for  general  comparisons  the 


D.  H.  HILL  LIBRARY 


26  THE  WORLD  OF  LIFE 

figures  obtainable  are  very  fair  approximations,  and  give  us 
interesting  and  valuable  information. 

About  one-third  of  the  total  numbe'r  of  our  species  of 
wild  flowering  plants  belong  to  what  the  late  Mr.  H.  C.  Watson 
termed  the  British  type ;  that  is,  they  are  found  in  suitable 
places  over  the  whole  of  Great  Britain,  and  in  most  districts 
are  so  plentiful  that  they  may  be  termed  common  plants  — 
such  are  the  Alder,  Birch,  and  Hazel  among  trees  and  shrubs ; 
the  Honeysuckle,  Ivy,  Heather  or  Ling,  Daisy,  Chickweed, 
!N^ettle,  and  a  host  of  others.  Another  gi'oup  is  abundant 
in  England,  but  absent  from  the  Highlands  or  from  Scotland 
generally,  such  as  the  Dwarf  Gorse  and  Yellow  Dead-Nettle. 
Several  arctic  or  alpine  plants  are  peculiar  to  the  Highlands, 
a  considerable  number  of  species  are  found  only  in  our 
eastern  counties,  while  as  many  or  more  are  characteristic  of 
the  west. 

More  curious  perhaps  than  all  these  are  the  cases  of 
plants  found  only  in  one  small  area,  or  two  or  three  isolated 
patches ;  and  of  others  which  are  limited  to  a  single  station, 
sometimes  of  a  few  acres  or  even  a  few  yards  in  extent. 
Such  are  the  Cotoneaster,  found  only  on  Great  Orme's  Head 
in  ]^.  Wales;  the  Yellow  Whitlow-Grass,  on  Worms  Head 
in  S.  Wales ;  the  pretty  white-flowered  Potentilla  rupestres, 
on  a  single  mountain-top  in  Montgomeryshire;  the  small 
liliaceous  plant,  Simetlius  hicolor,  in  a  single  grove  of  pine 
trees  near  Bournemouth,  now  probably  exterminated  by  the 
builder,  and  another  plant  of  the  same  family,  Lloydia 
serotina,  limited  to  a  few  spots  in  the  Snowdon  range ;  the 
beautiful  alpine  Gentiana  verna,  in  upper  Teesdale,  Yorkshire, 
and  others  confined  to  single  mountains  in  the  Highlands. 
Between  the  extremes  of  widespread  abundance  and  the 
greatest  rarity,  every  intermediate  condition  is  found ;  and 
this  is,  so  far  as  we  know,  a  characteristic  of  every  part  of 
the  world.  This,  again,  affords  a  striking  proof  of  that 
struggle  for  existence  which  has  already  been  referred  to, 
acting,  as  Darwin  was  the  first  to  point  out;  first  to  limit  the 


TEMPEEATE  FLOKAS 


27 


range  of  a  species,  often  so  that  it  exists  only  in  two  more  or 
less  isolated  areas,  then  to  diminish  the  number  of  individuals 
in  these  areas,  and  finally  to  reduce  them  to  a  single  group 
which  ultimately  succumbs  to  an  increased  stress  of  competi- 
tion or  of  adverse  climatal  changes,  when  a  species  which 
may  have  once  been  flourishing  and  widespread  akogether 
ceases  to  exist.  The  rarity  of  a  species  may  thus  be 
considered  as  an  indication  of  approaching  extinction. 

Numerical  Distribution  of  Plants  hi  Britain 

We  will  now  give  a  few  numerical  statements  as  to  the 
comparative  abundance  of  the  species  of  plants  in  large  and 
small  areas  in  various  parts  of  the  world,  such  facts  having  a 
special  application  to  the  theory  of  evolution.  The  55 
counties  of  England  and  Wales  (counting  the  three  Ridings 
of  Yorkshire  as  counties)  have  usually  areas  from  500  to 
2500  square  miles;  and  a  considerable  number  of  them 
have  had  their  plants  enumerated  in  special  catalogues  or 
floras.  The  following  are  the  approximate  numbers  of  the 
flowering  plants  in  a  few  of  these :  — 


Statistics  of  County  Floras 

County. 

Area,    Sq.   Miles. 

No.   of   Species. 

Carnarvonshire    

563 
1357 

980 
1533 

790 
1612 

840 

636 
1519 
2638 

233 
2658 

1056 

Cornwall   

1140 

Dorsetshire 

1010 

Essex  

1010 

Glamorganshire  

950 

Hampshire    

1150 

Herefordshire     

865 

Hertfordshire 

890 

Kent    

1120 

Lincolnshire   

1200 

Middlesex   

835 

West    Yorkshire 

995 

Mean  of  the  12  counties 

1198 

1026 

Great    Britain 

87,500 

1800 

28 


THE  WOELD  OF  LIFE 


This  table  of  the  distribution  of  plants  in  our  counties 
is  very  instructive,  because  it  shows  us  the  influence  of 
diversity  of  soils  on  the  number  of  species  that  can  grow 
and  maintain  themselves  naturally  as  wild  plants.  This  is 
largely  dependent  on  the  extreme  diversity  of  the  geology  of 
our  island,  almost  every  geological  formation  from  the  oldest 
to  the  most  recent  being  rej^resented  in  it.  This  variety  of 
soil  seems  to  be  much  more  important  than  diversity  of  sur- 
face due  to  altitude,  so  that  our  lowland  counties  are  quite 
as  rich  as  those  which  are  hilly  or  mountainous.  Again,  we 
see  that,  within  moderate  limits,  greater  area  has  little  in- 
fluence on  richness  of  the  flora,  the  largest.  West  Yorkshire, 
having  only  about  one-fifth  more  species  than  the  smallest, 
Middlesex,  with  only  about  one-twelfth  the  area. 

The  preponderating  importance  of  variety  of  soil  and  sur- 
face conditions  affording  good  stations  for  plants,  such  as 
woods,  hedgerows,  streams,  bogs,  etc.,  is  well  shown  by  a  few 
special  comparisons  that  have  been  made  by  experienced 
botanists. 

The  Parish  of  Cadney  (Lincolnshire),  a  little  over  3  square 
miles  in  area,  has  720  species  of  flowering  plants;  the  county 
nearly  900  times  as  large,  having  1200. 

The  Parish  of  Edmondsham  (in  Dorsetshire),  covering  less 
than  3  square  miles,  has  640  species ;  the  county,  340  times 
as  large,  having  1010  species. 

An  equally  remarkable  instance  was  given  by  Mr.  H.  C. 
Watson  fifty  years  ago,  and  no  doubt  from  his  own  observa- 
tions, as  he  resided  in  the  countv. 


Area, 

Sq.   Miles. 

Species. 

Surrey    

760 
60 
10 

1 

840 

An  area  in  Surrey  of    

660 

600 

"      at  Thames  Ditton,  Surrey.  •  - 

400 

TEMPEEATE  FLOIUVS  29 

Here  we  see  that  10  square  miles  coutaiiied  nearly  as  many 
species  as  60,  and  nearly  two-thirds  the  nmiibcr  in  TOO  square 
miles ;  while  the  single  square  mile  produced  nearly  half  the 
number  in  the  whole  county. 

Taking  still  smaller  areas,  Mr.  Woodruffe-Peacock  found 
fields  in  Lincolnshire  and  Leicestershire,  of  from  10  to  25 
acres,  to  yield  from  50  to  60  species  of  plants ;  while  a  plot 
of  16 Vo  feet  square  (or  1  perch)  would  usually  have  20  to  .')0 
species.  Old  and  long-disused  stone-quarries  are  often  very 
rich,  one  of  about  two  acres  producing  sometimes  as  many 
species  as  the  fields  of  eight  or  ten  times  the  area.  On  a  plot 
of  turf  3  feet  by  4,  at  Down  in  Kent,  Mr.  Danvin  found  20 
species  of  flowering  plants  growing. 

These  facts  of  the  distribution  of  plants  in  our  own  is- 
lands prove,  that  for  moderately  large  areas  in  the  same 
country  possessing  considerable  diversity  of  soil  and  general 
conditions  affecting  plant-life,  the  majority  of  the  species  are, 
as  a  rule,  so  widely  scattered  over  it  that  approximately  similar 
areas  produce  a  nearly  equal  number  of  species.  Further, 
we  find  that  areas  of  successively  smaller  and  smaller  sizes  have 
a  very  much  greater  number  of  species  relatively  than  larger 
ones ;  so  that,  as  we  have  seen,  10  square  miles  may  show  al- 
most as  much  variety  in  its  plant-life  as  an  adjacent  area 
of  60  square  miles,  and  that  a  single  square  mile  may  some- 
times contain  half  the  number  of  species  foimd  in  700  square 
miles. 

This  characteristic  of  many  small  areas  being  often  much 
richer  in  proportion  to  area  than  larger  ones  of  which  they 
form  a  part,  is  a  necessary  result  of  the  great  differences  in 
the  areas  occupied  by  the  several  species  and  the  numbers 
of  the  individuals  of  each ;  from  those  very  common  ones  which 
occur  abundantly  over  the  whole  country,  to  others  which,  al- 
though widespread,  are  thinly  scattered  in  favourable  situa- 
tions, down  to  those  exceptional  rarities  which  occur  in  a  very 
few  spots  or  in  very  small  numbers.  Those  spots  or  small 
areas  which  present  the  most  favourable  conditions  for  plant- 


30  THE  WORLD  OF  LIFE 

life  and  are  also  most  varied  in  soil,  contour,  water-supply, 
etc.,  will,  when  in  a  state  of  nature,  be  occupied  by  a  large 
proportion  of  the  common  and  widespread  plants,  together 
with  so  many  of  the  less  common  or  the  rare  species  which 
find  the  requisite  conditions  in  some  part  of  its  varied  soil 
and  aspects,  as  to  produce  that  crowding  together  of  species 
and  luxuriance  of  growth  which  are  such  a  joy  to  the  botanist 
as  well  as  to  the  less  instructed  lover  of  nature. 

All  these  peculiarities  of  vegetation  are  to  be  met  with  in 
every  part  of  the  world,  and  often  in  a  more  marked  degree 
than  with  us.  But  this  depends  very  much  on  diversities  of 
climate  and  on  the  extent  of  land  surface  on  which  the  entire 
flora  has  been  developed.  The  total  number  of  species  de- 
pends mainly  on  these  two  factors,  and  especially  on  the 
former.  The  variety  of  species  is  small  in  arctic  or  sub-arctic 
lands,  where  the  long  and  severe  winter  allows  of  only  certain 
forms  of  vegetable  and  animal  life;  and  it  is  equally  if  not 
more  limited  in  those  desert  regions  caused  by  the  scarcity 
or  almost  complete  absence  of  streams  and  of  rain.  It  is  most 
luxuriant  and  most  varied  in  that  portion  of  the  tropics  where 
the  temperature  is  high  and  uniform  and  the  supply  of  mois- 
ture large  and  constant,  conditions  which  are  found  at  their 
maximum  in  the  Equatorial  Zone  within  twelve  or  fifteen 
degrees  on  each  side  of  the  equator,  but  sometimes  extend- 
ing to  beyond  the  northern  tropic,  as  on  the  flanks  of  the 
Himalavas  in  north-eastern  India,  where  the  monsoon  winds 
carrv  so  much  moisture  from  the  heated  Indian  Ocean  as  to 
produce  forests  of  tropical  luxuriance  in  latitudes  where  most 
other  parts  of  the  world  are  more  or  less  arid,  and  very  often 
absolute  deserts. 

Temperate  Floras  compared 

I  will  now  endeavour  to  compare  some  of  the  chief  floras 
of  the  Temperate  Zone,  both  as  regards  the  total  number  of 
species  in  fairly  comparable  areas,  and  the  slight  but  clearly 


TEMPERATE  FLOEAS 


oi 


marked  increase  of  the  number  in  more  southern  as  compared 
with  more  northern  latitudes. 

I  will  first  show  how  this  law  applies  even  in  the  com- 
paratively slight  difference  of  latitude  and  climate  within  our 
own  country.  Dividing  Great  Britain  (without  Wales)  ^  into 
three  nearly  equal  portions  —  Scotland  north  of  the  Forth  and 
Clyde,  Mid-Britain,  and  South  Britain,  including  all  the 
southern  counties;  with  areas  of  22,000,  26,000,  and  31,000 
square  miles  —  the  number  of  species  (in  1870)  was,  respec- 
tively, 930,  1148,  and  1230.  At  the  same  period  the  total  of 
Great  Britain  was  1425  species.  These  figures  are  all  ob- 
tained from  Mr.  H.  C.  Watson's  Cybele  Britannica,  and  must 
therefore  be  considered  to  be  fairly  comparable.  We  see  here 
that  the  whole  of  the  Scottish  Highlands,  with  their  rich  alpine 
and  sub-alpine  flora,  together  with  that  of  the  sheltered  valleys, 
lakes,  and  mountainous  islands  of  the  west  coast,  is  yet  de- 
cidedly less  rich  in  species  than  Mid-Britain,  while  both  are 
less  rich  than  South  Britain,  with  its  more  uniforai  surface, 
but  favoured  with  a  more  southern  climate. 

The  following  table  shows  these  facts  more  distinctly :  — 


Area, 
Square  Miles. 

No.   of 
Species. 

North   Britain 

22,325 
26,550 
31,050 

930 

Mid-Britain,  Lowlands  south  to  Stafford  -^ 

and  Leicester J 

South  Britain   ( Wales  excluded ) 

1148 
1230 

The  above  figures  have  been  kindly  extracted  from  Wat- 
son's volume  by  my  friend  the  late  Mr.  W.  H.  Beeby. 

Making  a  comparison  of  some  countries  of  Europe  we  have 
similar  results  more  clearly  shown. 

1  Wales  is  omitted  in  order  to  make  the  three  divisions  more  equal,  and 
contrasted  in  latitude  only. 


32 


THE  WOELD  OE  LIEE 


Floras  of  Europe,  showing  Influence  of  Latitude 


Countries. 


Europe    

Lapland   

Scandinavia    and 
Denmark    .  .  .  . 

Sweden     

Britain     

Germany    

Switzerland     .  .  . 

France    

Italy     

Sardinia     

Sicily    


Area. 
Square  Miles. 


No.  of 
Species. 


;3,850,000 
150,000 
456,000 

173,000 

87,500 

208,000 

16,000 

204,000 

91,400 

9,300 

9,940 


9500 

500 

1677 

1165 
1860 
2547 
2454 
4260 
4350 
1770 
2070 


Nyman 

A.  De  Candolle 


(( 


Lend.   Cat.,   1895 

Garehe,   1908 

Schinz  and  Kellar,    1908 

Coste,  1906 

Beccari 


The  above  table  shows  us  a  continuous  and  well-marked 
increase  as  we  go  from  north  to  south,  the  irregularities  in 
this  increase  being  well  accounted  for  bj  local  conditions  and 
by  allowing  something  for  differences  of  area.  Sweden  is  so 
much  poorer  than  Britain,  owing  to  its  having  been  completely 
ice-clad  during  the  glacial  epoch,  while  much  of  southern  Brit- 
ain was  free.  Gennany  is  poorer  than  Erance,  partly  on 
account  of  its  severer  continental  climate,  but  also  owing  to 
Erance  possessing  a  greater  variety  of  surface,  owing  to  its 
including  a  portion  of  the  loftiest  Alps  in  the  south-east,  the 
isolated  Pyrenees  in  the  south,  the  Jura  and  Vosges  mountains 
on  the  north-east,  and  its  central  volcanic  ranges,  together  with 
its  southern  Mediterranean  coast,  and  a  very  extensive  west- 
ern and  northern  coast-line.  It  also  has  a  more  diversified 
soil,  owing  to  far  less  of  its  surface  being  buried  under  glacial 
debris.  Italy  has  still  greater  advantages  of  a  similar  kind, 
and  its  slight  superiority  to  Erance,  with  less  than  half  the 
area,  is  about  what  we  should  expect.  It  well  illustrates  the 
fact,  already  ascertained,  that  difference  of  area  within  moder- 
ate limits  is  of  far  less  importance  than  comparatively  slight 
advantages  in  soil  and  climate. 


TEMPERATE  ELOEAS 


33 


Turning  now  to  N'orth  America,  the  following  figures  from 
the  latest  authorities  have  been  supplied  by  my  friend  Mr. 
J.  D.  A.  Cockerell :  — 


state. 


Montana     and    Yellowstone 

Park 

Nebraska   

Colorado    

California    


Area, 
Square   Miles. 


150,000 

118,000 
104,000 
158,000 


No.  of 
Species. 


1934 

1478 
2872 
2700 


Remarks. 


Data    in    1900 

1898 
1900 
"      recent 


Two  subdivisions  of  the  eastern  United  States  show  well  the  effects 

of  latitude. 


Central       and       north-east  ~ 
States  —  Michigan           to  L 

736,000 

32r98 

Recent    estimate 

Virginia,    Kentucky 

South-east  United   States .... 

630,000 

6321 

et                   (( 

The  number  of  species  in  proportion  to  area  and  position 
is  apparently  less  than  in  Europe,  though  the  corresponding 
latitudes  are  farther  south.  Germany  and  Switzerland  com- 
bined, with  an  area  less  than  one-third  of  the  north-eastern 
and  central  States,  have  about  as  many  species ;  while  Erance, 
in  about  the  same  average  latitude,  but  with  less  than  one- 
third  the  area,  has  considerably  more.  The  south-eastern 
States  extending  to  30°  S.  lat.  have  about  the  same  number 
of  species  as  Europe  from  the  Alps  and  Carpathians  south- 
ward, while  the  area  of  the  latter  is  very  much  smaller  and 
its  latitude  about  eight  degrees  farther  north. 

The  whole  Mediterranean  flora  was  estimated  bv  Griesbach 
and  Tchikatcheff,  in  1875,  to  comprise  7000  species  in  an  area 
of  about  550,000  square  miles ;  so  that  the  best  comparisons 
that  we  can  make  between  large  European  and  American  areas 
show  a  decided  superiority  in  the  former.  This  is  no  doubt 
partly  due  to  the  much  severer  winter  climate  in  correspond- 
ing latitudes  of  !N'orth   America ;    and   perhaps   the   long  per- 


84  THE  WORLD  OE  LIFE 

sistence  of  siicli  conditions  before  the  glacial  period  may  be 
the  main  cause  of  the  whole  phenomenon. 

It  is,  however,  in  temperate  Asia  that  we  find  what  seem 
to  be  the  richest  extra-tropical  floras,  at  least  in  the  north- 
ern hemisphere.  The  great  work  of  Boissier,  Elora  Orientalis 
(1880),  describes  11,876  species  in  the  region  of  East  Europe 
and  South- West  Asia,  from  Greece  to  Afghanistan  inclusive, 
the  area  of  which  may  be  roughly  estimated  at  2,000,000 
square  miles.  It  is  a  region  of  mountains  and  deserts  inter- 
mingled wdth  luxuriant  valleys  and  plains,  and  almost  trop- 
ically warm  in  its  southern  portion.  So  much  of  it  is  diffi- 
cult of  access,  however,  that  the  collections  hitherto  made 
must  fall  far  short  of  being  complete.  Its  extreme  richness 
in  certain  groups  of  plants  is  showm  by  the  fact  that  Boissier 
describes  757  species  of  Astragalus  or  Milk-vetch,  a  genus  of 
dwarf  plants  spread  over  the  w^hole  northern  hemisphere,  but 
nowhere  so  abundant  as  in  this  region.  Europe  has  120 
species.  • 

The  only  other  extensive  area  in  temperate  Asia  the  plants 
of  which  have  been  largely  collected  and  recently  catalogued 
(by  Mr.  W.  B.  Ilemsley  of  the  Kew  Herbarium)  is  China 
and  Corea,  occupying  a  little  more  than  1%  million  square 
miles.  The  enumeration,  completed  in  1905,  shows  8200 
species  of  flow^ering  plants  actually  described.  But  as  large 
portions  of  this  area  have  never  been  visited  by  botanists, 
and  as  new  species  w^re  still  flowing  in  rapidly  at  the  close 
of  the  enumeration,  there  can  be  little  doubt  that  the  total 
will  reach,  before  many  years  have  elapsed,  10,000  or  per- 
haps 12,000  species.  It  is,  moreover,  an  area  that  is  es- 
pecially rich  in  trees  and  shrubs,  and  as  these  are  less  col- 
lected by  the  travelling  botanist  than  the  herbaceous  plants, 
it  becomes  still  less  easy  to  speculate  on  the  actual  number 
of  species  this  country  really  contains.  Japan,  which  is  prob- 
ably better  known,  has  about  4000  species  in  less  than  one- 
tenth   the  area,   and  is  thus   a  little   richer  than   Erance.     It 


TEMPERATE  ELOEAS  35 

agrees,  however,  very  closely  with  the  AVestern  Himalayas  as 
estimated  by  Sir  J.  D.  Hooker. 

Coming  to  the  southern  hemisphere,  we  find  several  ex- 
amples of  exceedingly  rich  floras.  The  first  to  be  noticed  is 
Chile,  where,  in  an  area  of  250,000  square  miles,  5200  species 
of  flowering  plants  have  been  found.  In  Australia,  Xew  South 
Wales,  with  an  approximately  equal  area,  has  3105  species, 
while  West  Australia  has  3242  species  in  what  is  probably 
not  more  than  one-fourth  the  area,  as  so  much  of  that  Colony 
is  absolute  desert. 

But  richer  than  either  of  these  is  extra-tropical  South 
Africa,  where,  in  about  a  million  square  miles,  13,000  species 
are  known,  and  there  are  still  probably  many  to  be  added. 
The  richest  portion  of  this  area  is  the  Cape  Eegion,  as  de- 
fined by  Mr.  H.  Bolus,  where,  in  30,000  square  miles,  there 
are  about  4500  species  of  flowering  plants.  This  area  is  the 
same  as  that  of  southern  Britain,  and  about  one-third  that  of 
West  Australia  excluding  the  tropical  portions  and  the  desert. 

All  these  rich  areas  in  the  southern  hemisphere  agree  in 
one  respect,  they  are  limited  inland  hj  mountains  or  deserts, 
and  their  coast-line  is  bordered  by  a  considerable  extent  of 
sea  less  than  1000  fathoms  deep,  and  another  still  larger 
extent  under  2000  fathoms.  There  is  thus  a  high  prob- 
ability that  in  all  these  cases  the  flora  was  originally 
developed  in  a  much  larger  and  more  varied  area,  and  that 
it  has  been,  in  comparatively  recent  times,  very  greatly  re- 
duced in  extent,  thus  crowding  the  various  species  together. 
This  has,  no  doubt,  caused  the  extinction  of  some,  while 
others  show  that  they  are  on  the  road  to  extinction  by  their 
limitation  to  very  narrow  areas,  as  is  especially  the  case  with 
many  of  the  orchids,  the  heaths,  and  other  characteristic 
South  African  groups.  Of  course  the  mere  submergence  of 
a  large  amount  of  lowlands  would  not,  of  itself,  enable  any 
of  its  plants  to  invade  the  adjacent  undisturbed  land;  but 
the    subsidence    would    no    doubt    have    been    very    slow,    and 


36 


THE  WOELD  OE  LIFE 


might   have    included    the    degradation    of    lofty    mountains. 

It  Avould  also  be  accompanied  by  a  lowering  of  some  of  the 
existing  area.  This  would  modify  the  climate  in  various 
ways,  leading  probably  to  a  higher  temperature  and  more 
moisture,  thus  giving  more  favourable  conditions  generally 
for  a  great  variety  of  plants. 

For  easy  reference  it  may  be  well  to  give  here  a  table 
showing  the  main  facts  as  to  these  warm-temperate  floras. 

Warm-Temperate  Floras  compared 
Northern   Hemisphere 


Country. 


S.E.   United   States. 

Mediterranean 

Greece  to  -j 

Afghanistan         j 

China  and  Corea. .  . 

Japan    

Himalayas,  West. .  . 
Algeria   


Area, 
Square  Miles. 


630,000 
550,000 

2,000,000 

1,500,000 
150,000 
150,000 
150,000 


No.  of 
Species. 


6,321 
7,000 

11,876 

8,200 
4,000 
4,000 
2,930 


T.  D.  A.  Coekerell 
Tchikateheff 

Boissier,     Flora 
talis,   1880 
Hemsley,   1905 
Havati,  1908 
Hooker,  1906 
Matthews,   1880 


{ 


Orien- 


Chile 

Souther 

250,000 
310,700 

?  90,000 

88,000 

26,380 

103,650 

1,000,000 

30,000 

n  Eemiepheri 

5,200 
3,105 

3,242 

1,830 

965 

1,474 

13,000 

4,500 

? 

• 

N.S.    Wales 

W.    Australia 

Victoria    

Miiller 

r    "      (tropics   and 
\             deserts   omitted ) 

Miiller 

Tasmania    

ii 

New  Zealand 

South    Africa 

The    Cape   Region .  . 

Cheeseman,   1906 
Thomer's  Census 
H.   Bolus,   1886 

Temperate  Floras  of  Smaller  Areas  compared 

We  will  now  deal  with  a  series  of  smaller  areas  (com- 
parable to  our  counties)  which  I  have  been  able  to  collect 
from  various  parts  of  the  world ;  and  I  propose  to  arrange 
them  in  order  of  latitude,  from  north  to  south,  so  as  to  show 
still    more   distinctly    the   influence    of   climate.     Each    main 


TEMPERATE  ELOEAS 


37 


division  of  the  globe  will  be  considered  separately  for 
convenience  of  reference,  and  we  begin  with  Europe,  for  wbicli 
materials  are  the  most  accessible,  though  still  far  from  abun- 
dant. 

The  recent  publication  of  a  flora  of  Harjedal,  a  province 
of  central  Sweden,  with  a  mountainous  surface  and  abundant 
forests,  shows  how  poor  is  a  sub-arctic  area  which  has 
recently  been  buried  under  an  ice-sheet.  The  real  wonder  is 
that  it  should  have  acquired  so  rich  a  flora  by  the  natural 
means  of  dispersal  from  more  southern  lands. 


Temperate  Floras  of  Small  Areas  in  Europe 


Locality. 


I 

C 
< 

a, 


Harjedal    (Sweden),    lat.    61°-64' 

Malvern  Hills 

Hertford     (near) 

Strasburg,  lat.  48 J ° 

Schaflniiausen 

Thurgau  

Basel 

Zurich     

St.   Gallen 

r  Schwyz,  Uri,  Underwalden , 

<  Glarus     

I  Uri    

r  Grisons , 

^  Valais,    464° 

tTicino,    46J° 

Ofengebietes,    Grisons 

Vallee  de  Joiix,  Jura , 

Bergunerstocke,   Engadine 

Poschiavo,  S.  of  Bernina  Pass ... 

Euganean    Hills,    Padua 

Susa,    Piedmont    (Beccari) 

Ferrara,   Valley  of  Po    (Beccari) 

Mytilene   (Lesbos)    (Candargy)  .  . 


Area, 
Sq.  Miles. 

No.  of 
Species. 

5375 

606 

120 

802 

80 

810 

120 

960 

114 

1220 

381 

1006 

163 

1117 

666 

1151 

779 

1295 

950 

1352 

267 

1100 

415 

1160 

2773 

1550 

2027 

1752 

1088 

1504 

86 

797 

100 

823 

47 

873 

92 

1200 

795 

1400 

540 

2203 

1012 

794 

675 

1249 

Remarks. 


Birger.  1908 

De  Candolle 
(( 

a 

H.  H.  Field 

(( 
it 
it 
it 
it 
it 
it 

a 

Lat.  46°40' 
Lat.  46°40' 
Lat.  46°30' 
46°20' 
45°30' 
45°  10' 
44°50' 
39°00' 


(I  am  indebted  to  Mr.  Herbert  H.  Field  for  all  the  data 
in  this  table,  except  where  otherwise  stated.     They  are  from 


38  THE  WOELD  OF  LIFE 

the  original  authorities,  and  he  has  kindly  brought  them 
up  to  date  as  far  as  possible,  so  that  they  may  be  fairly  com- 
parable.) 

Although     very     unequal     in     extent,     the     various     Swiss 
cantons,   which   form  the  bulk   of   this   table,   are   remarkably 
similar  in  their  botanical  riches,  the  smallest,  most  northerly, 
and  least  alpine   (Schaffhausen)   having  more  than  two-thirds 
the    number    of    species    of    the    Valais,    the    most    southerly, 
nearly   the   largest,   and  the   most   alpine,   the   main   chain  of 
the  Alps  for  nearly  100  miles  forming  its  southern  boundary, 
and  the  Bernese  Alps   its  northern,     But   Schaffhausen   geo- 
graphically  connects   eastern   France   wdth   western   Germany, 
and  partakes  of  the  rich  flora  of  both  countries.     This  table 
of  the   Swiss   cantons  is  also  very  interesting  in   showing   us 
that  alpine  floras   are  really  no  richer  in  species   than  those 
of  the  lowlands,   if  we   compare   approximately   equal   areas. 
A   remarkable   illustration   of   this   is   the   comparison   of   the 
Ofengebietes,   a   district  including   snowy   peaks,   forests,    and 
lowland    meadows,    having    almost    exactly    the    same    number 
of   species   as   an   equal   area   near   Strasburg,    or   one   around 
the  town  of  ITertford !     Switzerland,   thouirh   so   verv   unlike 
Great   Britain   in   situation,   climate,    and   physical   conditions 
generally,    yet    reproduces    in    its    cantons    that    curious    uni- 
formity  in   species-production  that   we   found   to   be   the   case 
in   our   counties.     But   as   Switzerland,   though   only   one-fifth 
of   our   area,   has   a   gTeater   number   of   species   by   one-third, 
that  superiority  is,  as  a  rule,  reproduced  in  its  subdivisions. 
Susa,   in  Piedmont,  wdth  its  fertile  valleys  and  snowy  Alps, 
has  by  far  the  richest  flora   of  the  whole   series,   due  to   its 
w^arm  climate,  variety  of  surface,  and  complete  shelter  from 
the  north.     Mytilene,   the   farthest   south,   has   doubtless   been 
impoverished  botanically  by  its  large  population  and  extensive 
fruit  culture. 

It  is,  I  think,  clear  that,  other  things  being  equal,  an 
alpine  flora  is  not  at  all  richer  than  a  lowland  one ;  but,  as 
we  shall  see  further  on,   there   are   indications   that   the   high 


TEMPERATE  FLORAS  39 

alpine  flora  really  partakes  of  that  poverty  wliicli  appertains 
to  liigii  latitudes.  It  is  the  novelty  and  beauty  of  alpine 
plants  that  are  so  attractive  to  the  botanist  and  so  entrancing 
to  the  lover  of  nature,  that  give  an  impression  of  abundance 
which  is  to  some  extent  deceptive,  and  this  is  increased  by 
the  fact  that  Avhole  groups  of  plants  which  are  more  or  less 
rare  in  the  lowlands  are  plentiful  at  higher  altitudes.  Two 
other  circumstances  add  to  this  impression  of  abundance  — 
alpine  flowers  are  mostly  very  dwarf,  and  being  all  at  the 
same  level,  attract  the  eye  more  than  when  distributed  over 
various  heights  from  that  of  the  creeping  herb  to  the  summit 
of  lofty  trees ;  and,  in  addition  to  this,  the  shortness  of  the 
season  of  growth  leads  to  a  much  larger  proportion  of  the 
species  flowering  together  than  on  the  lowlands  at  the  same 
latitude. 

Extra-European   Temperate   Floras 

The  number  of  floras  which  are  available  for  comparison 
with  those  of  Europe  are  few  in  number  and  yqxj  widely 
scattered ;  but  they  serve  to  illustrate  the  fact  already  dwelt 
upon,  that  the  dift'erences  of  species-j^opulation  in  fairly  com- 
parable areas  approach  to  a  general  uniformity  all  over  the 
world. 

Boulder  County  is  probably  one  of  the  most  favourably 
situated  areas  in  the  United  States.  It  is  onlv  a  little  west 
of  the  centre  of  the  country;  it  comprises  warm  valleys  and 
one  of  the  highest  of  the  Rocky  Mountain  summits.  Long's 
Peak,  and  being  in  the  latitude  of  southern  Italy  and  Greece, 
has  abundant  sunshine  and  a  warm  summer  temperature. 
It  thus  agrees  in  physical  conditions  with  some  of  the  alpine 
cantons  of  Switzerland,  and  the  number  of  its  flowering 
plants  is  almost  identical  with  the  average  of  Zurich,  St.  Gall, 
Schwyz,  etc.,  which  have  almost  the  same  mean  area. 

Washington,  D.C.,  with  an  undulating  surface  just  above 
the  sea-level,  and  a  fair  amount  of  forest  and  river-swamp, 
agrees    very   well   with    the    mean    of   Strasburg   and    Schaff- 


40 


THE  WOKLD  OF  LIFE 


Extra-European  Temperate  Floras.     Small  Areas. 


Lat. 


40°N. 
39°N. 


37°N. 
37°N. 


35  °S. 

35*S. 

34°S. 

32rs. 

27rS. 

27J°N. 


Country. 


North  America. 
Boulder   Co.,   Colorado. . . 
Washington,  D.C 

Japan. 

Mount  Nikko 

Mount   Fujiyama 

South  Africa. 
Cape  Peninsula 

Aust7nlia. 

Illawarra,    N.S.W 

Cumberland  Co.,  N.S.W. . 
Mudgee  (Wellington  Co.) 
Brisbane,  Q 

North    India. 
Temperate   Sikhim 


Area 
Sq.  Miles. 


751 
108 

360 
520 

197 

200 

1400 

600 

800 

1800 


No.  of 
Species. 


1200 
922 

800 
730 

1750 

829 
1213 

631 
1283 

2000 


Remarks. 


Cockerell 
Ward 

Hayati 

Bolus 

A.  G.  Hamilton 
W.  Woolls 
A.  G.  Hamilton 
Jas.  Wedd 

Hooker 


liausen,  somewhat  similarly  situated,  but  at  a  higher  latitude. 

The  two  mountain  areas  in  Japan,  which  Mr.  Hajati 
informs  me  have  been  well  explored,  show  an  unexpected 
poverty  in  species,  being  much  below  any  of  the  Swiss  cantons 
of  equal  area.  This  is  the  more  remarkable  as  Japan  itself 
is  equal  to  the  most  favoured  countries  in  Europe  —  France 
and  Italy;  and  this  again  indicates  the  combined  effect  of 
altitude  and  insularity  in  diminishing  species-production,  the 
lower  parts  of  these  Japan  mountains  being  highly  cultivated. 

In  the  southern  hemisphere  we  come  first  to  the  Cape 
Peninsula,  as  limited  by  Mr.  Bolus,  and  often  thought 
to  be  the  richest  area  of  its  size  in  the  world.  There  are  80 
species  of  heaths  and  nearly  100  species  of  orchises  in  this 
small  tract  only  a  little  larger  than  the  Isle  of  Wight.  'No 
other  similar  area  in  the  temperate  zone  approaches  it, 
though  it  is  possible  that  an  equally  rich  area  of  the  same 
extent  might  be   found   in  temperate   Sikhim,   where  several 


TEMPEEATE  ELOEAS  41 

distinct  floras  meet  and  intermingle.  But  as  the  Valais  is 
nearly  as  rich  as  Sikhim,  and  Susa  with  one-fourth  the  area 
is  still  richer^  it  is  quite  possible  that  smaller  areas  may 
be  found  as  rich  as  that  of  the  Cape  Peninsula.  The  best 
third  of  the  Susa  district  would  probably  approach  closely 
if  it  did  not  quite  equal  it.  Temperate  Australia  is  another 
country  which  has  obtained  a  high  reputation  for  its  floral 
riches,  for  much  the  same  reason  as  the  Cape  of  Good  Hope. 
In  1810  Robert  Brown  made  known  the  extreme  interest 
of  the  Australian  flora,  both  from  its  numerous  hitherto  un- 
known types  of  vegetation  and  the  variety  and  beauty  of  its 
flowering  shrubs.  It  was  therefore  supposed  that  the  country 
was  not  only  botanically  rich  in  new  species  and  genera,  but 
actually  so  in  the  number  of  its  species  in  proportion  to  area, 
and  this  may  really  be  the  case  with  limited  portions  of  West 
Australia  (for  which  I  have  been  able  to  obtain  no  detailed 
information),  but  is  certainly  not  the  case  for  Xew  South 
Wales,  Victoria,  or  Tasmania.  Cumberland  County,  which 
contains  Sydney  and  the  celebrated  Botany  Bay,  is  only  a 
little  richer  than  our  counties  of  about  the  same  area,  while 
the  celebrated  district  of  Illawarra  only  produces  about  the 
same  number  of  plants  as  does  Middlesex,  which  has,  ex- 
clusive of  London,  a  less  area.  Many  parts  of  Europe  in  a 
similar  latitude  are  much  more  productive. 

There  is,  however,  one  world-wide  group  of  plants  in 
which,  as  regards  small  areas,  eastern  temperate  Australia 
seems  to  be  pre-eminent  —  that  of  terrestrial  Orchids.  Mr. 
H.  Bolus,  in  his  work  on  the  Orchids  of  the  Cape  Peninsula, 
states  that  there  are  102  species  in  an  area  of  197  square 
miles ;  and  he  quotes  Mr.  Eitzgerald,  the  authority  on  the 
Orchids  of  Australia,  that  "  within  the  radius  of  a  mile  ''  he 
remarks,  "  certainly  no  such  concentration  would  be  found 
on  the  Cape  Peninsula."  I  think  it  probable  that  the 
"  radius  of  a  mile ''  is  meant  a  mile  bevond  the  citv  and 
suburbs  of  Svdnev,  in  which  case  it  mio'ht  bo  an  area  of 
from   10   to  20   square   miles.     Or  it  might   mean   a   picked 


42  THE  WORLD  OF  LIFE 

area  of  about  4  square  miles  of  uncultivated  land  some  miles 
away.  That  this  latter  is  quite  possible  is  shown  by  my 
friend  Mr.  Henry  Deane,  who  has  for  many  years  studied 
the  flora  of  20  square  miles  of  country  around  Hunter's  Hill, 
on  the  Paramatta  Kiver,  to  the  north-west  of  Sydney,  and  he 
here  obtained  59  species  of  Orchids  out  of  a  total  of  618 
flowering  plants.  The  sequence  of  the  first  eight  orders  in 
number  of  species  is  as  follows :  — 


1.  Orchidese    51) 

2.  Myrtaceae 5.5 

3.  Leguminosse     53 

4.  Pioteacese    35 


5.  Compositae  32 

6.  Graminese  31 

7.  Cyperacese  30 

8.  Epacridese  25 


In  XcAv  South  Wales,  as  a  Avhole,  Leguminosse  are  first 
and  Orchids  fifth  in  order.  There  is  probably  no  other 
purely  temperate  flora  in  which  Orchids  so  distinctly  take 
the  first  place  as  in  the  vicinity  of  Sydney. 

The  contrast  in  the  numbers  of  species,  in  approximately 
comparable  areas,  between  these  two  groups  of  waiTQ-temperate 
floras  is  fairly  well  marked  throughout,  there  being,  with  few 
exceptions,  a  decided  preponderance  in  the  southern  hemis- 
phere. South  Africa  is  undoubtedly  richer  than  China,  though 
its  area  is  less ;  and  perhaps  than  the  oriental  region  of  Bois- 
sier;  Avhile  Chili  compares  favourably  with  Japan  or  the  West- 
ern Himalayas.  Still,  the  differences  are  not  very  pronounced, 
and  are  such  as  appear  due  to  their  past  history  rather  than  to 
any  existing  conditions.  Those  in  the  northern  hemisphere 
(except  perhaps  in  the  case  of  the  Mediterranean  coasts)  have 
probably  been  for  a  considerable  period  stationary  or  expand- 
ing; while  those  in  the  south  have  almost  certainly  been  far 
more  extensive,  and  in  later  geological  time  have  been  contrac- 
ting, and  thus  crowding  many  species  together,  as  already  ex- 
plained. 


CHAPTER  IV 

TJIE    TEOPICAL    FLORAS    OF    THE    WORLD 

Although  the  idea  of  the  tropics  is  always  associated  with 
that  of  a  grand  develojiment  of  luxuriant  vegetation,  yet  this 
characteristic  by  no  means  applies  to  the  whole  of  it,  and 
the  inter-tropical  zone  presents  almost  as  much  diversity  in 
this  respect  as  the  temperate  or  even  the  frigid  zones.  This 
diversity  is  due  almost  wholly  to  the  unequal  and  even  er- 
ratic distribution  of  rainfall,  and  this  again  is  dependent  on 
the  winds,  the  ocean  currents,  and  the  distribution  and  ele- 
vation of  the  great  land  masses  of  the  earth. 

Once  a  year  at  each  tropic  the  sun  at  noon  is  vertical  for 
a  longer  period  continuously  tlian  in  any  other  latitude,  and 
this,  combined  with  the  more  complex  causes  above  referred 
to,  seems  to  have  produced  that  more  or  less  continuous  belt  of 
deserts  that  occurs  all  round  the  globe  in  the  vicinity  of  those 
two  lines,  but  often  extending  as  far  into  the  tropics  as  into 
the  temperate  zone.  In  a  few  cases  similar  conditions  occur 
so  near  the  equator  as  to  be  very  difficult  of  explanation.  It 
will  be  instructive  to  review  briefly  these  arid  regions,  since 
they  must  have  had  considerable  influence  in  determining 
the  character  of  the  tropical  vegetation  in  their  vicinity. 
Beginning  with  the  Sahara,  pre-eminently  the  great  desert 
of  our  globe,  if  we  take  it  with  its  extension  across  Arabia, 
we  find  that  it  occupies  an  area  nearly  equal  to  the  whole 
of  Europe,  and  that  the  African  portion  extends  as  far  to 
the  south  as  to  the  north  of  tlie  tropic  of  Cancer.  It  thus 
eats  away,  as  it  were,  a  great  slice  of  what  in  other  continents 
is  covered  with  tropical  vegetation,  and  forms  a  vast  barrier 
separating  the   tropical    and    temperate   floras,   such   as   exists 

43 


44  THE  WORLD  OF  LIFE 

in  no  other  part  of  the  world.  Passing  eastward,  the  desert 
regions  of  Baluchistan,  Tibet,  and  Mongolia  are  situated 
farther  and  farther  north ;  while  abundant  rainfalls  and  a 
truly  tropical  vegetation  extend  far  beyond  the  tropic  into 
what  is  geographically  the  temperate  zone.  This  is  especially 
the  case  along  the  southern  slopes  of  the  Himalayas  and  their 
extension  into  Burma  and  southern  China. 

In  the  western  hemisphere  we  have  the  desert  regions  of 
Utah,  Arizona,  and  parts  of  northern  Mexico  all  in  the  tem- 
perate zone. 

In  the  southern  hemisphere  the  desert  interior  of  central 
and  western  Australia  reproduces  the  Sahara  on  a  smaller 
scale.  In  Africa  there  is  the  Kalahari  desert,  mostly  south 
of  the  tropic,  but  on  the  west  coast  extending  to  about  15° 
from  the  equator.  In  South  America  an  arid  belt  of  almost 
complete  desert  extends  along  the  coast  from  near  the  equator 
to  Coquimbo  in  Chili,  whence  crossing  the  Andes  it  stretches 
south-eastward  into  Patagonia.  Even  more  extraordinary  is 
the  fact  that  in  north-eastern  Brazil,  in  the  provinces  of 
Ceara,  Pernambuco,  and  Bahia,  are  considerable  areas  which 
have  such  small  and  uncertain  rainfall  as  to  be  almost  des- 
erts, and  are  practically  uninhabitable.  And  this  occurs 
only  a  few  hundred  miles  beyond  the  great  Amazonian  forests 
of  Maranham  in  3°  S.  latitude. 

With  the  exception  of  these  areas  of  very  deficient  rain- 
fall, it  will,  I  believe,  be  found  that  the  intertropical  regions 
of  the  globe  are  the  most  productive  in  species  of  plants, 
and,  further,  that  as  we  approach  the  equator,  where  the 
temperature  becomes  more  uniform  throughout  the  whole  year 
and  the  amount  of  rain  and  of  atmospheric  moisture  is  also 
more  evenly  distributed,  the  variety  of  the  species  reaches 
a  maximum.  There  is  some  evidence  to  show  that  this  is 
the  case  not  only  in  the  region  of  the  great  forests,  but  also 
in  those  less  humid  portions  which  are  more  or  less  open 
country  with  a  vegetation  of  scattered  trees  and  shrubs,  to- 
gether with  herbaceous   and   bulbous   plants   which   cover  the 


i 


TEOPICAL  FLORAS 


45 


ground  only  during  the  season  of  periodical  rains,  as  will  be 
shown  later  on. 

Tropical  Floras  —  Large  Areas 


Country. 


British   India 

The  Indian  Peninsula 

Burma    

Indo-China    

Malay  Peninsula 

Ceylon    

Java   

Philippines 

New  Guinea 

Queensland    

Tropical    Africa    south    of-* 

Sahara   / 

Madagascar  and  Mascarenes. 

Central  America  and  Mexico. 

Nicaragua    to    Panama 

Brazil 

Trinidad    , 

Jamaica 


Area, 
Square 
Miles. 


No.  of 
Species. 


1,300,000 

500,000 

172,000 

225,000 

35,000 

25,000 

50,000 
115,000 
310,000 

668,000 

6,500,000 
229,000 

910,000 

80,000 

3,200,000 

1,750 

4,200 


17,000 
4,500 
6,000 
7,000 
5,100 
2,800 

4,000? 

4,656 

6,000 

4,454 

18,300 
5,950 

12,000 
3,000 

22,800 
1,967 
2,720 


Authority. 


Sir   J.   D.   Hooker 
Hooker 

Gagnepain 

Gamble 

Hooker 

Koorders 

Merrill 

Lauterbach 

Bailey 

Thonner's   Census 
Thonner 

Hemsley 


Martius 

Harti 

Brittan 


The  Tropical  Flora  of  Asia 

As  no  part  of  the  Asiatic  continent  (except  the  Malay 
Peninsula)  approaches  within  eight  degrees  of  the  equator,  its 
tropical  area  is  very  limited,  barely  reaching  one  and  a  quarter 
million  square  miles;  and  even  if  we  add  to  it  the  whole  of 
the  Malay  Archipelago,  the  Philippines,  ^ew  Guinea,  and 
tropical  Australia,  it  will  not  much  exceed  two  millions.  Yet 
these  countries  are  in  general  so  richly  clothed  with  a  tropical 
vegetation,  that  the  actual  number  of  their  species  will  almost 

1  Mr.  W,  E.  Broadway,  who  has  collected  in  the  island,  informs  me  that 
some  hundreds  of  species  remain  to  be  discovered  in  Trinidad. 


16  THE  WORLD  OF  LIFE 

certainly  surpass  those  of  Africa,  with  three  times  their 
tropical  area,  and  may  approach,  though  I  do  not  think  they 
will  equal,  those  of  tropical  America,  or  even  of  tropical 
South  America  only.  Portions  of  this  area  have  been  well 
explored,  especially  the  great  peninsulas  forming  India 
proper,  Burma,  and  Indo-China ;  but  the  two  latter  are  only 
sufficiently  known  to  show  their  extreme  richness  botanically, 
and  the  same  may  be  said  of  the  numerous  large  islands  of 
^  the  Malay  Archipelago.  We  may,  I  think,  be  certain  that 
what  is  known  of  these  two  sub-regions  is  less  than  what  re- 
mains to  be  made  known. 

Sir  Joseph  Hooker  estimates  the  whole  flora  of  British. 
India  at  17,000  species,  including  the  desert  flora  of  the  Indus 
valley  and  the  rich  temperate  and  alpine  floras  of  the 
Himalayas  above  an  elevation  of  6500  feet  in  the  east  and 
above  4000  or  5000  in  the  west.  But  as  I  am  here  dealing 
with  tropical  floras,  it  is  only  necessary  for  me  to  give  such 
figures  as  are  available  for  the  specially  tropical  portions  of 
it. 

The  Indian  Peninsula,  bounded  on  the  north  by  a  curving 
line  of  hills  and  mountains  which  run  not  far  from  the  line 
of  the  geographical  tropic,  is  somewhat  poor  when  compared 
with  the  aboundino:  riches  of  Burma  and  Indo-China;  vet  it 
possesses  areas,  especially  in  the  Western  Ghats  and  the 
Xiigiris,  of  great  botanical  richness  and  beauty,  much  of  which 
is  still  inadequately  explored.  Arid  conditions  prevail  over 
much  of  its  surface,  both  in  the  north  and  in  the  central 
plains,  but  these  are  interspersed  w'ith  deep  moist  valleys 
containing  a  vegetation  allied  to  that  of  Assam.  As  a  result 
of  this  greater  aridity  than  that  of  the  countries  farther  east, 
the  peninsula  is  much  poorer  in  Orchids,  having  only  200 
species  against  700  in  Burma ;  but  it  has  a  great  excess  in 
Grasses,  L^mbellifer?e,  Labiatj:Te,  and  Boragine?e,  and  a  cor- 
responding poverty  in  Melastomaceo?,  Gesneracege,  Myrtacese, 
Palms,  and  other  more  peculiarly  tropical  orders. 

Ceylon,  though  so  closely  connected  with  the  peninsula,  has 


TKOPICAL  FLORAS  47 

a  distinct  flora,  nearly  800  of  its  species  and  23  of  its  genera 
being  '^  endemic/'  that  is,  wholly  peculiar  to  it.  It  has  much 
stronger  affinities  with  the  ]\ialayan  flora,  due  in  part,  no 
doubt,  to  its  moister  and  more  uniform  insular  climate,  but 
also  to  some  features  of  its  past  history. 

The  figures  given  in  the  table  of  the  chief  tropical  floras 
of  the  world  (p.  45)  indicate,  so  far  as  possible,  the  actual 
numbers  of  the  species  now  existing  in  collections,  and,  for 
purposes  of  comparison,  require  certain  allowances  to  be 
made. 

Burma  and  Tndo-China  are  much  less  known  than  Penin- 
sular India,  vet  in  a  smaller  area  each  has  a  considerably  laro;er 
number  of  species ;  while  the  Malay  Peninsula,  which  is  more 
completely  forest-clad,  is  in  proportion  to  its  area  still  richer, 
due  mainly  to  its  more  equable  equatorial  climate.  The  fol- 
lowinc:  table  of  the  chief  natural  orders  is  taken  from  Mr. 
Ilemsley's  Introduction  to  the  Flora  of  Mexico  and  Central 
America :  — 

British  Ixdia   (17,000  species) 


1.  Orchidere    1060 

2.  I^giiiiiinosiE     831 

3.  Glramineoe     800 

4.  Robiacese    611 

5.  Euphoibiacese    624 

6.  Acanthaceae    503 


7.  Compositae     598 

8.  Cypeiaceaj    385 

0.  Labiatae    331 

10.  Urticaceae    305 

11.  Asclepiadeae     249 

12.  Rosaceae    218 


The  sequence  of  the  orders  is  taken  from  Sir  J.  Hooker's 
Sketch  of  the  Flora  of  British  India,  a  most  interesting  and 
instructive  pamphlet  published  in  1906,  but  the  numbers  of 
species  are  inserted  from  Mr.  Hemsley's  work  dated  1888. 
Since  then  the  total  numbers  have  increased  from  13,647  to 
17,000,  about  one-fourth,  so  that  the  above  figures  will  have 
to  be  increased  in  that  proportion ;  but  they  will  have  increased 
unequally,  as  shown  by  the  fact  that  the  orchids  are  estimated 
by  Sir.  T.  Hooker  at  1600. 

There  is  apparently  no  other  extensive  region  as  varied 
in  soil  and  climate  as  British  India,  in  which  Orchids  occu]\v 
the  first  place  in  the  sequence  of  the  orders.     This  is  due  to 


48 


THE  WORLD  OF  LIFE 


their  great  numbers  in  Burma,  but  even  more  to  the  fact 
that  in  the  whole  range  of  the  Himalayas  epiphytic  Orchids 
extend  far  into  the  temperate  zone,  while  in  the  more  eastern 
ranges  they  are  pre-eminently  abundant.  This  is  well  shown 
by  the  well-explored  district  of  Sikhim,  in  which  Orchids  take 
the  first  place,  not  only  in  the  tropical  lowlands,  but  in  the 
temperate  zone  from  6500  to  11,500  feet  above  the  sea-level. 
It  is  possible  that  in  some  parts  of  the  temperate  Andes,  wdiere 
Orchids  are  known  to  be  extremely  plentiful,  the  same  pro- 
portion may  exist ;  but  no  such  district  appears  to  have  been 
yet  sufficiently  explored  by  botanists.  Before  going  further 
it  will  be  as  well  to  give  the  sequence  of  the  orders  in  the 
districts  already  referred  to. 

Tropical  Sikhim   (up  to  6500  feet)    (2000  species) 


1.  Orchideae    (1) 

2.  Leguminosae    (2) 

3.  Gramineae    (3) 

4.  Urticacese    (8) 

5.  Euphorbiaceae    (5) 


6.  Cyperaceae   (7) 

7.  Rubiacese    (4) 

8.  Compositae    (9) 

9.  Aselepiadeae 

10.  Acanthaceae    (6) 


The  numbers  enclosed  in  brackets  give  the  sequence  in 
Burma,  Avhich  is  very  similar,  except  that  Scitaminese  (the 
Gingerworts)  is  the  tenth  order,  while  Asclepiadese  is  ex- 
cluded. 

The  Malay  Peninsula  differs  still  more  from  the  flora  of 
north-eastern  India,  in  being  more  exclusively  equatorial  and 
typical  Malayan,  and  in  this  case  I  am  able,  through  the  kind 
assistance  of  Mr.  J.  T.  Gamble,  to  give  the  number  of  species 
for  the  first  twelve  orders,  which  will  be  interesting  for  com- 
parison with  others  to  be  given  further  on. 

Malay  Peninsula   (5138  species) 


1.  Orchidaceae    540 

2.  Rubiaceae    312 

3.  Leguminosae    266 

4.  Euphorbiaceae    255 

5.  Anonaceae     178 

6.  Palmae    163 

Ferns 


7.  Lauraceae   153 

8.  Gramineae    144 

9.  Zingiberaceae  (Scitamineae)  137 

10.  Gesneraceae    131 

11.  Acanthaceae    128 

12.  Cyperaceae    127 

368  species. 


Fig.  1. —  Forest  in  Kelantan,  jNIalay  Peninsula. 


TROPICAL  FLORAS  49 

This  may  be  considered  a  typical  Malayan  flora  of  the  low- 
lands, the  mountains  not  being  sufficiently  extensive  or  lofty 
to  favour  the  abundance  of  Composita'  found  in  Sikhini  and 
Burma;  while  the  Anonacese  (custard  apples);  the  Lauracege 
(true  laurels),  producing  cinnamon,  cassia,  and  many  other 
sj^ecies  and  odoriferous  nuts,  barks,  and  fruits,  and,  above 
all,  the  noble  order  of  Palms,  which  have  alwavs  been  con- 
sidered  the  most  characteristic  of  the  vegetable  productions  of 
the  tropics,  all  take  a  higher  place  than  in  any  part  of  India. 
Sir  Joseph  Hooker  estimates  the  known,  palms  of  Burma  at 
68,  so  that  it  is  hardly  probable  that  any  future  additions 
will  bring  them  to  an  equality  with  the  much  smaller  Malay 
Peninsula.  This  affords  another  illustration  of  the  increase 
in  the  number  of  species  of  Palms  as  we  approach  the  equator, 
and  renders  them,  with  the  Rubiacese,  the  Euphorbiacese,  and 
the  Orchids,  the  most  typical  of  equatorial  orders  of  plants. 

Through  the  kindness  of  Professor  R.  H.  Yapp  I  am  able 
to  give  here  two  beautiful  photographs  taken  by  himself  in 
the  Malayan  forests,  which  give  an  excellent  idea  of  the 
general  character  of  the  vegetation,  though  unfortunately  not 
many  of  the  trees  or  other  plants  shown  can  be  identified; 
but  a  few  remarks  may  be  made  as  to  their  general  charao- 
ter. 

Very  prominent  on  the  large  trunk  in  the  foreground  is 
the  bird's-nest  fern  (Asplenium  nidus),  very  common  in  the 
forests  and  also  in  our  hot-houses.  Above  it  is  a  climbing 
fern  (AcrosticJium  scandens).  On  the  left  is  a  light-coloured 
slender  tree  with  knobs  or  spines,  and  having  many  climbers 
about  it.     This  may  be  a  palm. 

Among  the  tangled  vegetation  in  every  direction  are  slender 
lines,  upright,  oblique,  or  beautifully  curved;  these  are  the 
lianas  or  forest-ropes,  many  being  rattans  (palms),  but  others 
belong  to  various  dicotyledonous  plants  of  many  natural  or- 
ders; and  these  form  one  of  the  most  constant  and  charac- 
teristic features  of  the  damp  equatorial  forests  both  in  the 
eastern  and  western  hemispheres.     The  slender  shrub  to  the 


50  THE  WOELD  OF  LIFE 

left,  with  a  spray  of  foliage  showing  light  against  the  dark 
trunk,  may  be  an  Ixora.  On  the  left,  crossing  the  spined 
trunk,  is  one  of  the  climbing  palms  or  rotangs  (commonly 
called  ^'rattan''  in  England),  while  the  dense  mass  of  vege- 
tation to  the  right  is  largely  composed  of  slender  bamboos. 

The  other  view  (Fig.  2)  is  more  characteristic  of  the  dense 
Malayan  forest,  where  trees  of  all  sizes,  climbers  of  many 
kinds,  and  tangled  undergrowth,  of  dwarf  palms,  shrubs,  and 
herbs,  fill  up  every  spot  on  which  plants  can  obtain  a  foot- 
ing. The  large  twisted  climber  in  the  foreground  is  perhaps 
a  Bauhinia  (Leguminosse),  thougli  it  may  belong  to  any  of 
a  variety  of  genera,  and  even  orders,  which  form  such  ropes. 
The  distinct  ribbed  leaf  showing  to  the  left  of  the  most 
tw^isted  part  is  probably  one  of  the  Melastomacege.  The  dwarf 
palms  in  the  foreground  are  also  very  characteristic.  Just 
above  where  the  twisted  climber  goes  out  of  sight  is  a  climb- 
ing fern  (Acrostichum  scandens),  and  it  seems  to  grow  on 
a  knobbed  or  spined  trunk  like  the  one  in  the  other  picture. 
A  close  examination  will  show  that  the  five  or  six  trunks 
of  tall  trees  visible  have  each  peculiarities  of  growth  or  of 
bark  which  prove  tbem  to  belong  to  quite  distinct  species. 
The  very  straight  one  to  the  left  of  the  rope-climber  is  a 
palm.  The  abundance  of  climbers  is  shown  by  the  numerous 
very  fine  wdiite  or  black  lines  here  and  there  crossing  the 
picture,  especially  in  the  lower  portion,  each  representing  a 
liana  or  forest-cord  striving  to  work  its  way  upward  to  the 
light.  In  the  original  photograph  the  tangled  mass  of  foliage 
in  the  foreground  is  seen  to  consist  of  a  great  variety  of  plants. 
The  fern  with  very  narrow  fronds  at  the  base  of  the  rope  is 
NepJu'oIejns  cordifolia,  while  the  large  closely  pinnate  leaves 
in  the  foreground,  as  well  as  the  smaller  ones,  truncate  at 
the  ends,  are  various  species  of  palms.  The  prints,  unfor- 
tunately, do  not  show  all  the  details  in  the  original  photo- 
graphs. 

Professor  O.  Beccari,  in  the  interesting  volume  on  his  ex- 
plorations   in   Borneo,    tells    us   that    when    building   a    house 


Fig    2. —  Forest  in  Perak.  ^fal.iv   Pcniiisiiln. 


TKOPICAL  FLORAS  51 

on  tlie  Mattang  inuunUiiii  in  Sarawak,  three  straight  trees, 
each  about  9  inches  diameter,  were  found  growing  at  such  a 
distance  and  position  as  to  be  exactly  suitable  for  three  of 
the  corner  posts  of  the  house  in  which  he  afterwards  resided 
during  some  months'  collecting  there.  When  the  tops  were 
cut  off,  and  he  could  examine  them,  he  found  them  to  be- 
long to  three  different  genera  of  two  natural  orders,  and  also 
that  they  were  all  new  species  probably  peculiar  to  Borneo. 
Another  illustration  he  gives  of  the  great  productiveness  of 
these  forests  in  species  of  trees  is,  that  in  the  two  months 
he  lived  in  his  forest  home  he  obtained  fifty  species  of 
Dipterocarps  (an  order  in  which  he  was  much,  interested)  in 
two  months'  collecting  and  within  a  mile  of  his  house.  This 
order  of  plants  consists  entirely  of  large  forest-trees,  and  is 
especially  characteristic  of  the  true  Malay  flora  from  the 
Peninsula  to  Java,  Celebes,  and  the  Philippines.  It  is  prob- 
ably at  its  maximum  in  Borneo,  as  Professor  Beccari  gives 
it  as  the  twelfth  in  the  sequence  of  orders  as  regards  number 
of  species:  (1)  Rubiace^e;  (2)  Orchidace^,  200  species;  (3) 
Euphorbiaceee ;  (4)  Leguminosse;  (5)  Anonace^e;  (6)  Melas- 
tomacene;  (7)  Palmse,  130  species;  (8)  Urticacese;  (9) 
Myrtacese;  (10)  Aracese;  (11)  Guttiferse;  (12)  Diptero- 
carpe?e,  60  species.  This  list,  it  must  be  remembered,  refers 
to  the  '^  primeval  forests "  alone,  taking  no  account  of  the 
widespread  tropical  flora  found  in  old  clearings  and  in  the 
vicinity  of  towns  and  villages. 

Before  leaving  the  Asiatic  continent  I  must  say  a  few  words 
as  to  the  figures  given  in  the  table  for  the  plants  of  Indo- 
China,  comprising  the  whole  territory  between  Buraia  aud 
China,  which  has  been  at  least  as  w^ell  explored  by  French 
botanists  as  have  Burma  and  the  Malay  Peninsula  by  our- 
selves. Having  been  unable  to  obtain  any  statistical  infor- 
mation on  this  area  from  English  botanists,  I  applied  to  ]\r. 
Gagnepain,  of  the  botanical  department  of  the  ^N^atural  His- 
tory Museum  of  Paris,  who  hns  kindly  furnished  me  witli 
the   following   facts.      They   have   at   the   Museum   very   large 


62  '     THE  WORLD  OF  LIFE 

collections  of  2)laiits  from  all  parts  of  tliis  territory,  collected 
from  1862  onwards,  but  great  numbers  of  the  species  are 
still  undescribed.  Only  small  portions  of  the  Hora  have  been 
actually  described  in  works  still  in  process  of  publication ;  but, 
from  his  knowledge  of  this  extensive  herbarium,  he  believes 
that  the  flora  of  Indo-China,  as  actually  collected,  comprises 
about  7000  species. 

Flora  of  the  Malay  Islands 

The  great  archipelago  (usually  termed  the  Malayan,  or 
^' Malaisia  "),  which  extends  from  Sumatra  to  Xew  Guinea, 
a  distance  of  nearly  4000  miles,  and  from  the  Philippines 
to  Timor,  more  than  1000  miles,  comprises  an  actual  land 
area  of  1,175,000  square  miles,  which  is  fully  equal  to  that 
of  all  tropical  Asia,  even  if  we  include  the  lower  slopes  of 
the  Eastern  Himalayas.  Tliis  great  land-area  has  the  advan- 
tage over  the  continent  of  being  mainly  situated  within  ten 
degrees  on  each  side  of  the  equator,  and  having  all  its  coasts 
bathed  and  interpenetrated  by  the  heated  waters  of  the  Indian 
and  Pacific  Oceans.  These  conditions  have  led  to  its  being 
almost  wholly  forest-clad,  and  to  its  possessing  a  flora  com- 
parable in  luxuriance  and  beauty  with  that  of  the  great 
Amazonian  plain,  situated  almost  exactly  at  its  antipodes. 

The  western  half  of  this  archipelago  has  undoubtedly 
been  united  with  the  continent  at  a  comparatively  recent 
geological  epoch,  and  this  portion  of  it,  both  in  its  animal 
and  vegetable  life,  is  nearly  related  to  that  of  the  Malay 
Peninsula  and  Siam ;  but  the  three  chief  islands,  Sumatra, 
Borneo,  and  Java,  are  of  such  great  extent,  and  have  such, 
differences,  both  of  geological  structure  and  of  climate,  as 
to  give  to  each  of  them  a  distinct  individuality,  combined 
with,  in  all  probability,  a  Avealth  of  species  fully  equal  to 
that  of  the  adjacent  continent.^     The  remainder  of  the  Archi- 

1  The  Director  of  Kew  Gardens  informs  me  that,  in  1850,  the  flora  of  the       ( 
"  Netherlands  India,"  extending  from  Sumatra  to  New  Guinea  but  exclud- 
ing the  Philippines,  was  estimated  by  the  Dutch  botanists  to  possess  0118 


TEOPICAL  FLORAS  53 

pelago  has  bad,  however,  a  different  origin,  and  has  been 
much  longer  isolated.  Celebes  and  the  Philippines  have  cer- 
tain features  in  common,  indicating  a  remote  but  partial  union 
with,  or  approximation  to,  the  Asiatic  continent,  and  probably 
subsequent  submergence  to  an  extent  that  has  greatly  impov- 
erished their  mammalian  fauna.  Xew  Guinea,  however, 
stands  alone,  not  only  as  the  largest  island  in  the  world  (ex- 
cluding Australia),  but  as,  in  some  respects,  the  most  remark- 
able, both  by  its  extraordinary  length  of  about  1500  miles, 
and  its  possession  of  a  range  of  snow-capped  and  glaciated 
mountains.  Biologically  it  is  unique  by  having  produced  the 
wonderful  paradise-birds,  numbering  about  50  species ;  while 
its  true  land-birds  already  known  amount  to  about  800  species, 
a  number  very  far  beyond  tliat  of  any  other  island  —  Borneo, 
with  its  almost  continental  fauna,  having  about  450,  and  the 
great  island-continent  of  Australia  about  500. 

But,  as  regards  plant-life,  this  vast  archipelago  is  much  less 
known  than  that  of  inter-tropical  Asia,  though  it  will,  I  believe, 
ultimately  prove  to  be  even  richer.  Of  the  two  larger  w-estern 
islands,  Sumatra  and  Borneo,  I  can  obtain  no  estimate  of  the 
botanical  riches,  and  the  same  is  the  case  with  the  whole  of 
the  Moluccas.  Java  is  better  known,  but  still  inadequately. 
There  remains  for  consideration  the  Philippines,  Celebes,  and 
^ew  Guinea,  as  to  which  we  have  recent  information  of  con- 
siderable interest. 

Since  the  Americans  have  established  themselves  in  the 
Philippines  they  have  done  much  to  make  known  its  natural 
products;  and  Mr.  E.  D.  Merrill,  botanist  to  the  Bureau  of 
Science  at  Manilla,  has  greatly  increased  our  former  scanty 
knowledge  of  its  very  interesting  flora.  He  has  been  so  kind 
as  to  send  me  several  of  his  published  papers,  as  well  as  a 
complete  MS.  list  of  the  families  and  genera  of  vascular  plants, 
with  the  number  of  species  known  to  inhabit  the  islands  up  to 

species  of  flowering  plants  then  known.  As  such  large  portions  of  all  the 
islands  are  almost  unknown  botanically,  it  seems  not  improbable  that  the 
actual  numbers  may  be  three  times  as  many. 


54  THE  WORLD  OF  LIFE 

August  1909.  This  shows  the  large  total  of  4656  indigenous 
flowering  plants  already  collected,  though  extensive  areas  in  all 
the  islands,  and  more  especially  in  the  great  southern  island 
Mindanao,  are  altogether  unexplored.  Besides  these,  there  are 
no  less  than  791  ferns  and  their  allies,  a  number  which  is 
probably  not  surpassed  in  any  other  country  of  equal  extent 
and  as  imperfectly  explored.  The  Malay  Peninsula  has  rather 
more  flowering  plants,  but  its  ferns  are  only  368,  as  given  in 
]\rr.  Eidley's  list,  issued  in  1908.  The  following  is  the 
sequence  for  the  first  twelve  orders  (excluding  introduced 
plants)   from  Mr.  Merrill's  lists:  — 

Philippixes   (4G56  species) 


1.  Orchideffi    372 

2.  Eubiacese    267 

3.  Leguminosae     258 

4.  Euphorbiacese     227 

5.  Urticaceae,  with  ]\Ioraceae   .  .  221 
G.  Graminese       215 


7.  Cyperaceae    137' 

8.  Myrtaceae   105 

9.  Palmse    100 

10.  Asclepiadeae 94 

11.  Melastomaceae   86 

12.  Compositae   83 


Ferns 791  species. 

Comparing  this  with  the  Malay  Peninsula  (jd.  18),  we  find 
the  first  four  orders  in  similar  places  of  the  sequence,  while 
Anonacese,  ScitamineiT,  and  Melastomacese  give  way  to  Myr- 
tacese,  Palma^,  and  Asclepiadeae. 

The  Philippine  flora  has  a  large  proportion  of  its  species 
peculiar  to  it.  In  some  families,  such  as  the  Ericaceae,  Ges- 
neracese,  Pandanacese,  etc.,  almost  all  are  so.  Among  species 
of  limited  range  some  interesting  facts  have  been  ascertained 
by  Mr.  Merrill.  Of  identical  or  closely  allied  species  in  sur- 
rounding countries,  39  have  been  found  to  extend  to  northern 
India,  38  to  China,  and  21  to  Formosa,  while  only  9  have  been 
noted  in  the  nearer  islands  of  Borneo,  Java,  and  Sumatra. 
But  the  most  decided  similarity  is  found  between  the  Philip- 
pines and  Celebes,  76  species  having  been  found  either  identical 
or  represented  by  allied  species ;  and,  considering  how  very 
imperfectly  the  Celebesian  flora  is  known,  the  amount  of  simi- 
larity may  be  expected  to  be  really  very  much  greater.     A  sim- 


TEOPICAL  PLOKAS  55 

ilar  relation  of  the  mammals,  birds,  and  insects  of  the  two 
island  groups  have  been  pointed  out  in  my  Island  Life,  and 
leads  to  the  conclusion  that  the  islands  have,  at  some  distant 
period,  been  almost  or  quite  united. 

The  Flora  of  Celebes 

Very  little  was  known  of  the  flora  of  this  extremely  inter- 
esting island  till  1898,  wdien  Dr.  S.  H.  Koorders  published  a 
large  quarto  volume  of  nearly  750  pages,  giving  the  results  of 
his  own  collections  during  four  months  in  the  north-east  pen- 
insula (Minahasa)  together  with  all  that  had  been  made  known 
by  the  few  botanists  who  had  previously  visited  the  islands. 

Dr.  Koorders  himself  collected  or  examined  1571  species,  of 
which  nearly  700  were  trees ;  and  he  has  given  lists  of  468 
species  w-hich  had  been  collected  in  various  parts  of  the  island 
by  other  botanists,  making  a  total  of  2039  species  of  flowering 
plants.  The  great  peculiarity  of  the  flora  is  indicated  by  the 
fact  that  nineteen  of  the  genera  of  trees  are  not  kno^\Ti  in 
Java ;  wdiile  the  affinities  are,  on  the  whole,  more  Asiatic  than 
Australian,  as  is  the  case  with  the  animals.  The  closest  affin- 
ity is  W'ith  the  Philippines,  as  with  the  birds  and  mammals, 
as  indicated  by  a  new  genus  of  trees  (W allacesdendron  celehi- 
cwn),  allied  species  having  been  since  found  in  the  adjacent 
group.  Dr.  Koorders  also  remarks  that  some  of  the  plants 
have  very  peculiar  forms,  almost  comparable  with  those  I  have 
pointed  out  m  its  butterflies.  One  of  these  is  no  doubt  the 
new^  fig-tree  (Ficus  minaliassa) ,  a  drawing  of  which  forms  the 
frontispiece  of  this  volume.  It  is  about  40  feet  high,  the 
fruits  hanging  thickly  from  the  branches  in  strings  3  or  4  feet 
long,  giving  it  a  very  remarkable  appearance.  His  general 
result  is,  that  the  flora  is  very  rich  in  peculiar  species,  but 
rather  poor  in  peculiar  genera. 

As  this  work  is  wholly  in  Dutch,  I  cannot  give  further 
details,  but  having  counted  tlie  species  in  each  natural  order 
I  will  add  a  list  of  the  ten  largest  orders  for  comparison  with 
others  here  given  :  — 


56 


THE  WOELD  OF  LIFE 


\ 


1.  Urticaeese 158 

2.  Legviminosse 105 

3.  Rubiacese    103 

4.  Euphorbiaceae    100 

5.  Orchideae 81 


6.  Palmaeeae 78 

7.  Gramineae 71 

8.  Compositse   63 

9.  :\Iyrtaeea». 58 

10.  Meliaceae    58 


I  will  add  a  few  words  on  a  point  of  special  interest  to 
myself.  Having  fonnd  that  tlie  birds  and  mammals  of  the 
eastern  half  of  the  Archipelago  Avere  almost  wholly  different 
from  those  in  the  western  half,  and  that  the  change  occurred 
abrnptly  on  passing  from  Bali  to  Lombok,  and  from  Borneo 
to  Celebes  (as  explained  in  chapter  xiv.  of  my  Malay  Archi- 
pelago), the  late  Professor  Huxley  proposed  that  the  straits 
between  them  should  be  called  ''  Wallace's  Line,"  as  it  forms 
the  boundary  between  the  Oriental  and  Australian  regions. 
But  later,  as  stated  in  my  Island  Life,  I  came  to  the  conclu- 
sion that  Celebes  was  really  an  outlier  of  the  Asiatic  continent 
but  separated  at  a  much  earlier  date,  and  that  therefore  Wal- 
lace's Line  must  be  dra^vn  east  of  Celebes  and  the  Philippines. 

The  Flora  of  New  Guinea 

Early  botanical  explorers  in  Kew  Guinea  were  disappointed 
by  finding  the  flora  to  be  rather  poor  and  monotonous.  This 
was  the  case  with  Prof.  O.  Beccari,  who  collected  on  the  north- 
w^est  coast;  and  Mr.  H.  O.  Forbes,  of  the  Liverpool  Museum, 
informs  me  that  he  formed  the  same  opinion  so  long  as  he  had 
collected  on  the  lowlands  near  the  coast,  but  that  on  reaching 
a  height  of  near  1000  feet  a  much  richer  and  quite  novel  flora 
was  found.  Prof.  Beccari,  who  is  at  this  time  studying  the 
palms  from  various  recent  Dutch,  British,  and  German  collec- 
tions, now  thinks  that  the  number  of  species  in  Xew  Guinea 
is  probably  as  gTeat,  in  equal  areas,  as  in  Borneo  or  the  Malay 
Peninsula,  but  that  the  species  are  not  so  distinctly  marked 
as  in  those  countries.  Thev  are  what  he  terms  second-ffrade 
species  as  compared  with  the  first-grade  species  of  the  latter. 
But  he  forms  this  opinion  chiefly  from  the  palms,  of  which 
he  makes  a  special  study. 


TKOPICAL  riOKAS  57. 

Dr.  Lauterbach,  who  is  engaged  in  describing  the  new  plant- 
collections  recently  obtained,  is  evidently  much  impressed  by 
them.  He  states  that  down  to  1905  there  were  known  from 
German  Xew  Guinea  2048  species  of  flowering  plants,  while 
about  1000  additional  species  had  been  found  in  other  parts 
of  the  island.  But  the  last  Dutch  expedition,  from  the  por- 
tions of  the  collections  he  has  examined,  will  probably  add 
another  1000  species.  Again  he  says  that  from  collections 
recently  made  by  Schlechter  in  German  Xew  Guinea,  and 
through  letters  from  him,  an  ^'  immense  increase  in  the  number 
of  species  is  in  prospect.'^  A  few^  more  years  of  such  energetic 
collecting  will  disclose  more  of  the  treasures  of  this  the  largest 
of  the  great  tropical  islands,  while  its  grand  central  chain  of 
mountains  may  be  expected  to  produce  a  large  amount  of  nov- 
elty and  beauty.  Dr.  Lauterbach's  conclusion,  in  a  letter  to 
Prof.  Beccari,  is  as  follows :  "  I  believe,  indeed,  that  one  would 
not  estimate  it  too  highly  if  one  reckoned  the  sum  total  of  the 
Papuan  Phanerogams  at  a  round  number  of  10,000."  Con- 
sidering that  ^ew  Guinea  has  more  than  double  the  area  of 
the  Philippines  (which  Mr.  Merrill  also  estimates  may  con- 
tain 10,000  species)  ;  that  it  is  nine  times  the  area  of  the 
Malay  Peninsula,  which  has  already  more  than  5000  species 
described;  that  it  has  the  enormous  length  of  1500  miles,  all 
between  0°  and  11°  of  S.  latitude;  that  it  has  an  extremely 
varied  outline ;  that  it  possesses  abundant  diversity  of  hill  and 
valley,  and  a  central  range  of  mountains  which  have  now  been 
proved  to  rise  far  above  the  line  of  perpetual  snow ;  and  finally, 
that  it  is  almost  everywhere  clad  with  the  most  luxuriant  for- 
ests, and  enjoys  that  moist  and  equable  equatorial  climate 
which  is  proved  to  be  most  favourable  to  vegetable  as  well  as 
to  insect  life,  it  seems  to  me  probable  that  it  may  ultimately 
prove  to  be  among  the  richest  areas  on  the  earth's  surface.  In 
bird-life  it  seems  likely  to  surpass  any  other  equal  area,  and  it 
may  do  so  in  plants  also,  but  In  the  luxuriance  of  insect-life 
I  am  inclined  to  think  that  it  will  not  equal  the  richest  por- 
tions of  equatorial  America. 


68  THE  WORLD  OF  LIFE 

The  only  other  tropical  flora  in  the  eastern  hemisphere  in- 
cluded in  my  table  is  that  of  Queensland,  which  is  mostly 
within  the  tropics,  but  a  large  part  of  the  interior  consists  of 
elevated  plains  with  a  rather  arid  climate  where  little  of  the 
luxuriance  of  tropical  vegetation  is  to  be  met  with.  Probably 
not  more  than  one-fourth  of  the  area  is  clothed  with  a  typical 
tropical  vegetation,  but  this  has  as  yet  been  very  partially 
explored  botanically.  The  number  of  species  compares  best 
with  that  of  the  Indian  peninsula,  with  wdiich  it  agrees  nearest 
in  area ;  and  both  these  countries,  though  very  rich  in  certain 
districts,  cannot  be  considered  to  present  examples  of  the  full 
luxuriance  of  tropical  vegetation. 

Floras  of  Tropical  Africa  and  America 

The  floras  of  the  remainder  of  the  tropics  are,  for  various 
reasons,  of  less  interest  for  the  purposes  of  this  work  than 
those  of  the  eastern  hemisphere,  and  a  very  brief  reference  to 
them  wdll  be  here  given.  Although  Africa  has  a  tropical  area 
nearly  equalling  those  of  Asia  and  America  combined,  it  has  a 
flora  of  less  extent  and  of  less  botanical  interest  than  that 
of  either  of  them.  Its  area  of  luxuriant  tropical  forest  is 
comparatively  of  small  extent,  and  much  of  it  is  yet  unex- 
plored, so  that  the  number  of  species  in  the  latest  enumeration 
is  perhaps  more  than  might  have  been  expected.  The  islands 
belonging  to  Africa  — ■  Madagascar,  Mauritius,  Bourbon,  and 
the  Seychelles  —  are,  however,  of  extreme  interest,  on  account 
of  the  remarkable  character,  as  well  as  the  extreme  speciality, 
both  of  their  plants  and  animals.  As,  however,  these  pecul- 
iarities have  been  rather  fully  discussed  in  chapter  xix.  of  my 
Island  Life,  it  is  not  necessary  to  repeat  them  here.  I  may 
state,  however,  that  in  Mauritius  there  are  about  40  peculiar 
genera,  nearly  all  of  shrubs  or  trees,  while  no  less  than  5 
peculiar  genera  of  palms  are  found  in  the  Seychelle  Islands. 
The  following  table  of  tlie  sequence  of  orders  in  Madagascar 
may  be  of  interest  for  comparison  with  those  of  other  large 
floras. 


TROPICAL  FLOEAS  59 

Madagascar   (5000  species) 


1.  Leguminosae 346 

2.  Compositae   281 

3.  Euphorbiaceae    228 

4.  Orchideae      170 

Ferns 


5.  Cyperaceae    160 

6.  Rubiaceaj    147 

7.  Acantluiceae   131 

8.  Giamineae    130 

318  species. 


The  above  table  was  made  when  the  whole  flora  consisted 
of  3740  known  species.  As  it  is  now  increased  to  nearly  5000, 
the  figures  given  will  have  to  be  increased  by  one-third  on  the 
average.  But  as  this  increase  may  be  very  unequal,  they  have 
been  left  as  sriven. 


Flora  of  Tropical  America 

We  have  seen  reason  to  believe  that  the  temj^erate  flora  of 
^orth  America  is  somewhat  poorer  than  that  of  Europe  and 
northern  Asia,  though  the  south  temperate  zone  as  represented 
by  Chili  is  exceptionally  rich.  But  there  can  be  little  doubt 
that  its  whole  tropical  flora  is  extremely  rich ;  and  it  may  not 
improbably  be  found  to  contain  nearly  as  many  species  of 
plants  as  all  the  rest  of  the  tropical  world.  This  may  per- 
haps be  indicated  by  the  fact  that  it  has  fourteen  or  fifteen 
natural  orders  quite  peculiar  to  it,  wdiile  the  remainder  of  the 
globe  has  about  the  same  number ;  but,  taking  account  of 
three  other  orders  that  are  almost  exclusively  American,  Mr. 
Hemsley  is  of  opinion  that  the  balance  is  on  the  side  of 
America. 

America  has  the  great  advantage  of  possessing  the  largest 
continuous  or  almost  continuous  extent  of  tropical  forest  on 
the  globe.  The  vast  Amazonian  plain  forms  its  central  mass 
of  about  two  millions  of  square  miles  of  almost  continuous 
forest.  From  this  there  are  northward  extensions  over  the 
Guianas  and  parts  of  Venezuela,  along  the  north-east  branch 
of  the  Andes  to  Trinidad,  and  thence  through  Panama  and 
Honduras  to  the  lowlands  of  eastern  and  western  Mexico. 
Southward  it  sends  out  numerous  branches  along  the  great 
river  valleys  into  central  and  western  Brazil,  and  thence  along 


60  THE  WORLD  OF  LIFE 

the  eastern  slopes  of  the  Andes  to  beyond  tlie  southern  tropic; 
while  all  along  the  Atlantic  coast  there  is  a  belt  of  equal  lux- 
uriance, spreading  out  again  in  the  extreme  south  of  Brazil 
and  Paraguay  to  about  30°  of  south  latitude.  We  could  thus 
travel  continuously  for  about  five  thousand  miles  from  Mexico 
to  northern  Argentina  in  an  almost  unbroken  tropical  forest, 
or  about  the  same  distance  down  the  Amazon  valley  to  Par- 
anahyba  in  northern  Brazil,  and  then,  after  a  break  of  a  few 
hundred  miles,  along  the  east  coast  forests  for  about  two  thou- 
sand miles  more.  This  probably  equals,  if  it  does  not  surpass, 
the  tropical  forest  area  of  the  rest  of  the  globe. 

We  must  also  take  into  account  the  fact  that,  as  a  rule, 
tropical  forests  differ  from  those  of  the  temperate  zone  in  the 
s^^ecies  not  being  gregarious,  but  so  intermingled  that  adjacent 
trees  are  generally  of  distinct  species,  while  individuals  of  the 
same  species  are  more  or  less  widely  scattered.  When,  from 
some  commanding  elevation,  we  can  look  over  a  great  extent 
of  such  a  forest,  we  can  usually  see,  at  considerable  intervals, 
a  few,  perhaps  a  dozen  or  more,  small  patches  of  identical 
colour,  each  indicating  a  single  tree  of  some  particular  species 
which  is  then  in  flow^er.  A  few^  days  later  we  see  a  different 
colour,  also  thinly  scattered;  but  in  the  region  of  the  most 
luxuriant  tropical  forests  we  never  see  miles  of  country  thickly 
dotted  with  one  colour,  as  would  often  be  the  case  if  our  Euro- 
pean oaks  or  beeches,  birches  or  pines,  produced  bright-col- 
oured flowers.  This  fact  would  alone  indicate  that  the  tropical 
forests  are  wonderfully  productive  in  species  of  trees  and  woody 
climbers,  and  hardly  less  so  in  shrubs  of  moderate  size,  which 
either  live  under  the  shade  of  the  loftier  trees  or  line  the  banks 
of  every  river,  stream,  or  brooklet,  or  other  opening  to  which 
the  sun  can  penetrate.  In  those  latter  positions  there  is  also 
no  lack  of  herbaceous  plants,  so  that  the  whole  flora  is  exceed- 
ingly rich,  and  the  species  composing  it  rapidly  change  in 
response  to  the  slightest  change  of  conditions. 

The  difficulty  of  collecting  and  preserving  plants  in  these 
forest-clad  areas  is  so  great,  and  the  number  of  resident  bot- 


TEOPICAL  FLORAS  61 

anists  who  alone  could  adequately  cope  with  the  work  is  com- 
paratively so  small,  that  it  is  not  surprising  to  find  thai  the 
great  forest  region  of  tropical  America  is  still  very  imperfectly 
known.  Only  tw^o  considerable  areas  have  been  systematically 
collected  and  studied  —  in  ^orth  America  the  entire  tropical 
portion  from  South  Mexico  to  Panama  commonly  known  as 
'"  Central  America  " ;  and  in  South  America  the  vast  areas  of 
Brazil,  itself  comprising  more  than  half  of  tropical  South 
America.  The  comparatively  easy  access  to  this  latter  country, 
the  attraction  of  its  gold  and  diamond  mines,  its  extensive 
trade  with  England  and  with  other  civilised  countries,  have 
all  led  to  its  being  explored  by  a  long  series  of  botanists  and 
travellers,  the  result  of  whose  labours  have  been  incorporated 
in  a  moniimental  work,  the  Flora  Brasiliensis  of  Martins,  re- 
cently completed  after  more  than  half  a  century  of  continuous 
labour. 

The  number  of  species  described  in  this  work  is  22,800,  an 
enormous  figure  considering  that  its  area  is  less  than  half  that 
of  tropical  Africa,  and  that  probably  two-thirds  of  its  surface 
has  never  been  thoroughly  examined  by  a  botanist.  The  Cen- 
tral American  flora,  as  described  by  Mr.  Hemsley,^  in  less 
than  one-third  of  the  area  of  Brazil  has  about  12,000  species, 
and  this  is  no  doubt  a  much  nearer  approach  to  its  actual  num- 
bers than  in  the  case  of  Brazil. 

As  regards  the  additions  that  may  yet  be  made  to  that  flora, 
and  especially  to  the  great  forest  region  of  adjacent  countries, 
I  will  quote  the  opinion  of  a  very  competent  authority,  the  late 
Dr.  Bichard  Spruce,  who  assiduously  studied  the  flora  of  the 
Amazon  valley  and  the  Andes  for  fourteen  years,  and  himself 
collected  about  8000  species  of  flowering  plants,  a  large  pro- 
portion of  which  were  forest-trees.  In  a  letter  to  Mr.  Bentham 
from  Ambato  (Ecuador),  dated  22nd  June  1858,  he  writes:  "  I 
have  lately  been  calculating  the  number  of  species  that  yet 
remain  to  be  discovered  in  the  great  Amazonian  forest  from 

1  See  Biologia  Centrali  Americana,  by  Messrs.  Godman  and  Salveri; 
Botany,  4  vols.,  1888. 


62  THE  WORLD  OF  LIFE 

the  cataracts  of  the  Orinoco  to  the  mountaius  of  Matto  Grosso. 
Taking  the  fact  that  by  moving  away  a  degree  of  latitude  or 
longitude  I  found  about  half  the  plants  different  as  a  basis, 
and  considering  what  very  narrow  strips  have  up  to  this  day 
been  actually  explored,  and  that  often  very  inadequately,  by 
Humboldt,  Martins,  myself,  and  others,  there  should  still 
remain  some  50,000  or  even  80,000  species  undiscovered.  To 
any  one  but  me  and  yourself,  this  estimation  will  appear  most 
extravagant,  for  even  Martins  (if  I  recollect  rightly)  emits 
an  opinion  that  the  forests  of  the  Amazon  contain  but  few 
species.  But  allowing  even  a  greater  repetition  of  species  than 
I  have  ever  encountered,  there  cannot  remain  less  than  at  least 
half  the  above  number  of  species  undiscovered."  ^ 

Spruce  was  one  of  the  most  careful  and  thoughtful  of  writers, 
and  would  never  have  made  such  a  statement  without  full  con- 
sideration and  after  weighing  all  the  probabilities.  In  the 
same  letter  he  describes  how,  when  leaving  the  Uaupes  River 
after  nine  months  of  assiduous  collecting  there  in  a  very  lim- 
ited area,  a  sunny  day  after  continuous  rains  brought  out' 
numerous  flowers,  so  that  as  he  floated  down  the  stream  he 
saw  numbers  of  species  quite  new  to  him,  till  the  sight  became 
so  painful  that  he  closed  his  eyes  to  avoid  seeing  the  floral 
treasures  he  was  obliged  to  leave  ungathered !  At  Tarapoto 
he  observed  that  some  flowers  opened  after  sunset  and  dropped 
off  at  daAvn,  so  that  they  would  be  overlooked  by  most  collectors, 
while  of  many  the  flowering  season  was  very  limited,  sometimes 
to  a  single  day.  Join  to  this  the  scarcity  of  individuals  of 
many  species  scattered  through  a  trackless  forest,  and  it  is  evi- 
dent that  the  true  floral  riches  of  these  countries  will  not  be 
fully  appreciated  till  numerous  resident  botanists  are  spread 
over  the  entire  area. 

From  the  facts  of  distribution  given  by  Mr.   Hemsley  we 
learn  that  about  one-twelfth  of  the  species  of  Central  America 

1  See  Spruce's  Xotes  of  a  Botanist  on  the  Amazon  and  Andes,  vol.  ii.  p. 
208. 


TEOPICAL  FLORAS  63 

are  found  also  in  South  America,  and  that  about  TOO  are  found 
in  the  eastern  portion  from  Venezuela  to  Brazil,  so  that  prob- 
ably not  more  than  500  reach  the  latter  country.  The  com- 
bined floras  of  Brazil  and  Central  America,  even  as  now 
imperfectly  loiown,  will  therefore  reach  about  34,300  species. 
N^ow,  considering  how  very  rich  the  eastern  slopes  of  the  Andes 
are  known  to  be,  and  that  the  average  width  of  the  forest  zone 
between  Brazil  and  the  Andes  is  from  400  to  500  miles,  while 
the  plateaux  and  western  slopes  also  have  a  rich  and  distinct 
flora  and  fauna,  I  think  it  will  be  admitted,  that  whatever  the 
combined  floras  of  Brazil  and  Central  America  may  amount 
to,  that  number  will  be  nearly  or  quite  doubled  when  the  entire 
floras  of  Venezuela,  the  Guianas,  Colombia,  Ecuador,  and  Peru 
are  thoroughly  explored.  As,  roughly  speaking,  Brazil  con- 
tains about  half  the  great  tropical  forests  of  South  America, 
and  allowing  that  its  portion  is  the  best  kno^vn,  we  may  fairly 
add  one-third  of  Spruce's  lower  estimate  (25,000)  to  its 
present  numbers,  Avhich  will  bring  the  whole  to  very  nearly 
40,000  sjDecies.  By  doubling  this,  we  shall  reach  80,000  as 
the  probable  number  of  species  existing  in  tropical  South 
America. 

As  this  number  is  considerably  more  than  half  the  latest 
estimate  of  the  number  of  flowering  plants  yet  known  in  the 
whole  world  (136,000  species),^  more  than  half  of  which 
number  will  be  absorbed  by  the  comparatively  well-known  tem- 
perate floras,  it  will  be  apparent  that  we  have  at  present  a  very 
inadequate  idea  of  the  riches  of  the  tropical  regions  in  vege- 
table life.  This  result  will  be  further  enforced  by  additional 
facts  to  be  adduced  later. 

I  will  here  give  a  table  of  the  few  known  statistics  for  trop- 
ical America,  which,  though  very  fragmentary,  will  serve  to 
show  the  basis  on  which  the  preceding  estimate  of  probable 
numbers  rests. 

1  This  number  has  been  given  me  by  Mr.  W.  B.  Hemsley,  Keeper  of  the 
Kew  Herbarium,  as  being  that  of  Dr.  Tlionner  in  1008. 


64 


THE  WORLD  Or  LIFE 


Floras  of  Tropical  America 


Country. 

Area, 
Sq.  Miles. 

De 

scribed 
Species. 

Remarks. 

Mexico     (8.)     and    Cen-  1 

tral    America J 

Brazil   

910,000 

3,200,000 

79,000 

4,200 

1,750 

2,400 

12,000 

22,800 

3,000 

2,722 

1,967 

445 

Hemsley,   1888 
Martins 

Nicaragua  to  Panama .... 
Jamaica    

Hemsley 

L.   N.   Brittan,    1909 

Trinidad     

J.    H.   Hart,    1908 

CralaDasros    

(1902) 

Note. —  The  number  of  Trinidad  plants  is  from  a  Herbarium 
List  by  Mr.  J.  H.  Hart,  F.L.S.,  Superintendent  of  the  Botanical 
Gardens,  published  in  1908.  He  states,  however,  that  "a  large 
amount  of  material  has  not  been  arranged  under  natural  orders  " 
and  that  "the  later  added  specimens  have  not  been  arranged  for 
several  years  past."  But  he  adds,  "  As  it  now  stands,  there  is 
a  good  representation  of  the  Trinidad  flora." 

Mr.  W.  B.  Broadway  of  Tobago,  who  has  lived  several  years  in 
Trinidad  and  has  studied  its  flora,  informs  me  that  from  his  own 
observation  he  believes  that  many  hundreds  of  additional  species 
remain  to  be  collected;  and  this  is  what  we  should  expect,  as  the 
island  is  a  continental  one ;  while  Jamaica,  though  larger,  is  almost 
oceanic  in  character,  and  is  therefore  almost  certain  to  have  a  less 
complete  representation  of  the  tropical  American  flora  than  the 
former  island. 

The  great  work  on  the  flora  of  Mexico  and  Central  America 
deals,  unfortunately  for  my  present  purpose,  with  an  area  in 
which  temperate  and  tropical,  arid  and  humid  conditions  are 
intermingled  to  a  greater  extent  even  than  in  the  case  of 
British  India  already  referred  to.  Mexico  itself  comprises 
about  four-fifths  of  the  whole  area,  and  nearly  half  its  surface 
is  north  of  the  tropic  and  is  largely  composed  of  lofty  plateaux 
and  mountains.  It  thus  supports  a  vegetation  of  a  generally 
warm-temperate  but  rather  arid  type;  and  these  same  condi- 
tions with  a  similar  flora,  also  prevail  over  the  great  plateau 
of  southern  Mexico.     This   type   of  vegetation   extends   even 


TEOPICAL  FLORAS  65 

farther  south  into  the  uphuuls  of  (liiateinala,  so  that  we  only 
get  a  wholly  tropical  flora  in  the  small  southern  section  of  the 
area  from  Kicaragua  to  Panama. 

The  following  table  of  the  twelve  largest  orders  in  the  whole 
flora  Avill  be  of  interest  to  compare  with  that  of  British  India; 

Mexico  and  Central  America    (11,688   species) 


1.  Compositse   1518 

2.  Leguminosae     944 

3.  Orchidese    938 

4.  Gramineae     520 

5.  Cactaceae    500 

6.  Rubiaceae    385 


7.  Eiiphorbiacese    368 

8.  Labiata? 250 

9.  Solanaceae    230 

10.  Cyperaceae    218 

1 1.  Piperaeese     214 

12.  Malvaceae   182 


Ferns 545 

The  most  remarkable  feature  in  this  table  is  the  great  pre- 
ponderance of  Compositse  characteristic  of  all  the  temperate 
and  alpine  floras  of  America,  and  the  presence  of  Cactaceae, 
Solanaceae,  Piperaeese,  and  Malvaceae  among  the  12  predomi- 
nant orders,  the  first  of  the  four  being  confined  to  America. 

It  may  be  noted  that  of  the  12  most  abundant  orders  8  are 
the  same  in  these  two  very  widely  separated  parts  of  the  earth. 
But  even  this  table  greatly  exaggerates  the  actual  difference 
between  the  two  very  distinct  floras.  There  are  175  natural 
orders  in  British  India,  and  of  these  only  20  are  absent  from 
the  Mexican  region.  Of  these  20  orders  18  have  less  than  10 
species  (5  of  them  having  only  1  species),  so  that,  judging 
from  the  great  types  of  plants,  the  difference  is  wonderfully 
small.  We  can  therefore  understand  Sir  Joseph  Hooker's 
view,  that  there  are  only  two  primary  geographical  divisions  of 
the  vegetable  kingdom,  a  tropical  and  a  temperate  region. 

It  must  be  remembered,  however,  that  even  when  the  series 
of  orders  in  two  remote  areas  are  nearlv  identical,  there  mav 
be  a  very  marked  difference  between  their  floras.  Orders  that 
are  very  abundant  in  one  area  may  be  very  scarce  in  the  other ; 
and  even  when  several  orders  are  almost  equally  abundant  in 
both,  the  tribes  and  genera  may  be  so  distinct  in  form  and 
structure  as  to  give  a  very  marked  character  to  the  flora  in 


66  THE  WORLD  OF  LIFE 

which  they  abound.  Thus  the  Urticacese  include  not  only 
nettles,  hops,  and  allied  plants,  but  mulberries,  figs,  and  bread- 
fruit trees.  Even  Avith  so  much  identity  in  the  natural  orders, 
there  is  often  a  striking  dissimilarity  in  the  plants  of  distinct 
or  remote  areas,  owing  to  the  fact  that  the  genera  are  very 
largely  different,  and  that  these  often  have  a  very  distinct 
facies  in  leaf  and  flower.  Thus,  though  the  Myrtacese  are 
found  in  hot  or  warm  countries  all  over  the  world,  the  Euca- 
lypti, so  abundant  in  Australia,  give  to  its  vegetation  a  highly 
peculiar  character.  So  the  Onagracese  are  found  in  all  the 
temperate  regions,  yet  the  Fuchsias  of  South-temperate 
America    are    strikinoly    different    from    the    Willow-herbs    of 

CD    «- 

Europe  or  the  CEnotheras  of  ^^Torth  America ;  and  there  are 
thousands  of  equally  characteristic  genera  in  all  parts  of  the 
world. 

In  Mr.  Hemsley's  elaborate  table  of  the  General  Distribution 
of  Vascular  Plants,  he  gives,  in  Central  America,  the  number 
of  species  of  each  order  in  Nicaragua,  Costa  Rica,  and  Panama 
respectively,  these  three  states  constituting  the  tropical  section 
of  the  whole  area,  and  the  same  for  six  subdivisions  of  the  rest 
of  the  area.  But  the  numbers  added  together  will  give  more 
than  the  actual  number  of  species  in  the  combined  flora,  be- 
cause an  unlvnown  portion  of  the  species  will  be  found  in  two 
or  three  of  these  divisions.  But  he  gives  the  total  numbers 
for  these  three  states  and  also  for  the  remainder  of  the  nine 
areas.  He  also  gives  the  numbers  which  are  '^  endemic  "  in 
these  two  groups  of  areas  separately  and  in  the  whole  flora ;  I 
have  therefore  been  able  to  ascertain  the  proportion  which  the 
endemic  bear  to  the  total  in  Mexico  and  Guatemala,  which  I 
find  to  be  as  3  to  4  verv^  nearly,  so  that  by  deducting  one-fourth 
of  the  sum  of  the  species  in  these  areas  I  obtain  the  number 
existing  in  the  combined  area.  But  as  it  is  known  that  in  the 
tropics  species  have  a  less  range  than  in  the  temperate  zone, 
I  deduct  one-fifth  in  the  case  of  the  three  tropical  areas,  which 
will,  I  believe,  approach  very  nearly  to  the  actual  number  of 
species  in  the  combined  floras  as  given  in  the  following  table. 


TEOPICAL  FLOEAS  67 


Nicaragua,  Costa  Kica,  and  Panama   (3000  species) 


1.  Orchidcai    280 

2.  Conipositu?   107 

o.  LegLiiniiiQsaj     17(3 

4.  Riibiaeete    14(5 

5.  Uraminetp     iH) 

6.  Eiiphoibiacese    72 


7.  Gesneraceaj    GO 

8.  Cyperawa?    08 

0.  Alelastomacea^    07 

10.  Urticacoai 58 

11.  Aioideie    5-t 

12.  Palraai    50 


Ferns 252 

This  table  brings  out  clearly  the  extra-tropical  character  of 
Mexico  as  compared  with  these  tro|)ical  sections  of  Central 
America.  Xo  less  than  five  orders  of  the  former  twelve  have  to 
be  omitted  (Cactacea?,  Labiates,  Solanacese,  Piperaceas,  and  Mal- 
vaceae), which  are  replaced  by  the  more  exclusively  tropical  Ges- 
neracea?,  Melastomacese,  Urticacese,  xVroideae,  and  Palmte. 
Here,  in  two  adjacent  areas  differing  about  12°  in  mean  lati- 
tude, there  is  a  more  pronounced  difference  in  the  prevalent 
orders  of  plants  than  exists  between  two  great  regions  on  oppo- 
site sides  of  the  globe.  Another  characteristic  tropical  feature 
is  seen  in  the  large  number  of  ferns,  which  are  nearly  one- 
half  those  of  the  whole  number  found  in  Mexico  and  Central 
America,  which  has  an  area  nine  times  as  great. 

Of  the  other  tropical  American  floras  little  need  be  said. 
Jamaica  and  Trinidad  are  the  onlv  West  Indian  islands  of 
the  larger  group  for  which  I  have  been  able  to  get  recent 
figures.  Mr.  L.  ]^.  Brittan,  of  the  ]^ew  York  Botanical  Gar- 
dens, who  has  collected  in  the  former  island,  estimates  the 
species  at  2722,  which,  for  a  sub-oceanic  island,  is  a  large 
amount.  Trinidad,  which  is  almost  a  part  of  the  continent, 
should  be  much  richer,  and  its  existing  collections,  not  quite 
reaching  2000,  are  certainly  much  below  its  actual  number 
of  species.  The  Galapagos,  now  probably  fairly  well  known, 
but  possessing  only  445  species,  show  us  how  scanty  may  be 
the  flora  of  a  group  of  islands  of  considerable  size  and  situated 
on  the  equator,  when  the  conditions  are  not  favourable  for 
plant-immigration  or  for  the  gTowth  of  plants  at  or  near  the 
sea-level,  as  has  been  pointed  out  in  my  Island  Life. 


Q8  THE  WOKLD  OF  LIFE 

The  Flora  of  Lagoa  Santa 

There  is,  however,  one  small  area  in  the  Campos  of  Brazil 
in  about  20°  S.  lat.  and  2700  feet  above  the  sea-level,  which 
has  been  thoroughly  explored  botanically  bv  a  Danish  botanist, 
Professor  Eug.  Warming,  who  lived  there  for  three  years  with 
his  fellow-countrvman  Dr.  Lnnd,  who  first  studied  the  fossil 
vertebrates  in  the  caves  of  the  district.  This  was  in  1SG3-66; 
and  after  studying  his  collections  for  twenty-five  years  with  the 
assistance  of  many  other  botanists  he  published  in  1892  a 
quarto  volume  giving  a  most  careful  account  of  the  vegetation 
in  all  its  aspects,  with  numerous  very  characteristic  illustra- 
tions, both  of  individual  plants  and  of  scenery,  forming  one 
of  the  most  interesting  botanical  works  I  have  met  with.  Un- 
fortunately it  is  printed  in  Danish,  but  a  good  abstract  (about 
thirty  pages)  in  French  renders  it  accessible  to  a  much  larger 
body  of  readers. 

This  flora  is  strictly  limited  to  an  area  of  sixty-six  square 
miles,  so  that  every  part  of  it  could  be  easily  explored  on  foot, 
and  again  and  again  visited  as  different  species  came  into 
flower  or  ripened  their  fruit.  The  surface  is  undulating  and 
in  parts  hilly,  with  a  lake,  a  river,  some  low  rocky  hills, 
marshes,  and  numerous  deeply  eroded  ravines  and  valleys,  often 
with  perpendicular  rocky  sides,  where  there  is  perpetual  mois- 
ture and  a  rich  forest-vegetation.  But  everywhere  else  is  for 
half  the  year  arid  and  sun-baked,  covered  with  scattered  decid- 
uous trees  and  shrubs,  and  during  the  rains  producing  a  fairly 
rich  herbaceous  vegetation.  It  is,  in  fact,  a  good  example 
of  the  campos  that  occupy  such  a  large  portion  of  the  interior 
of  Brazil,  though  perhaps  above  the  average  in  productiveness. 

An  open  country  such  as  this  is,  of  course,  much  easier  to 
examine  thoroughly  than  a  continuous  forest,  which,  though 
actually  richer,  calls  for  a  much  longer  period  of  exploration 
before  all  its  riches  can  be  discovered.  But  though  the  coun- 
try  is  so  open,  with  trees  and  shrubs  spread  over  it  in  a  park- 
like manner,  Mr.  Warming  tells  us  that  trees  of  the  same  spe- 


TROPICAL  FLORAS 


69 


cies  are  so  widely  scattered  that  it  is  sometimes  difficult  to 
find  two  of  the  same  kind.  Another  interesting  fact  is,  that 
the  number  of  species  of  all  kinds  —  trees,  shrubs,  and  herbs  — 


ei 


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00 


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O 
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bD 


d   (VI 
Q 

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^   2 

B 

o 
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M 


is  twice  as  great  in  the  patches  of  forest  as  in  the  open  campos, 
while  the  two  are  so  distinct  that  he  believes  them  to  have 
hardly  a  species  in  common. 


TO  THE  WORLD  OF  LIFE 

Through  the  kindness  of  Professor  "Warming  I  am  able  to 
reproduce  here  a  few  of  his  characteristic  drawings  and  photo- 
graphs, with  descriptions  furnished  by  himself.  These  offer 
a  striking  contrast  to  the  photographs  of  typical  Malayan  vege- 
tation at  pp.  48  and  50. 

As  shewn  in  the  view  on  p.  69  (Fig.  3)  the  vegetation  cov- 
ering the  hills  is  w^hat  is  termed  ^^  cam2:)os  limpos,"  consisting 


Fig.  4. —  The  Campo  Cerrado;  Lapa  Vermelha  Rocks  to  the  Right. 

of  grasses  and  herbs  with  small  shrubs,  but  with  few  trees 
scattered  in  the  grass-land.  These  trees  are  low,  the  stems 
and  branches  tortnons  or  twisted.  In  the  valleys  where  the 
soil  is  richer  in  hnmus  and  always  moist,  there  is  thick  forest. 


TEOPICAL  FLOKAS 


71 


The  soil  in  all  the  campos  is  red  clay.  In  the  distance  is  seen 
the  smoke  of  fires  on  the  campos.  In  the  foreground  is  a 
''  campo  cerrado,"  i.e.  a  campo  with  many  trees,  but  never  so 
close  that  the  sun  does  not  shine  on  the  dense  carpet  of  high 
grasses  and  herbs  under  the  trees ;  which  latter  belong  mostly 
to  the  Leguminosge,  Ternstromiacese,  Vochysiacese,  Anonacese, 
Bignoniacese,  etc. 

Fig.  4  is  a  view  taken  in  the  "  Campo  cerrado,"  showing  the 
stunted  form  of  the  trees  which  characterise  it.  In  the  back- 
ground are  calcareous  cliffs,  in  which  are  the  fossil-producing 
caves.  At  the  foot  of  the  cliffs  the  trees  are  closer  and  higher ; 
and  on  the  top  is  a  more  open  and  dry  forest,  each  kind  of 
forest  having  its  peculiar  species  of  trees. 

Fig.  5  (facing  p.  72)  is  a  view  taken  close  to  the  rocks. 
The  upper  branches  of  Mimosas  and  other  trees  are  shown, 
which  grow  at  the  foot  of  the  cliffs,  one  of  them  being  a  tree 
of  the  custard-apple  family,  whose  branches  are  fruit-laden. 
Numerous  tall  cactuses  (Cereus  ccerulescens)  are  seen  growing 
up  from  the  rock  itself,  and  several  stinging  and  thorny  plants. 
Other  genera  growing  on  the  rocks  are  Opuntia,  Pereskia, 
Peperomia,  Epidendrum,  Tradescantia,  Gloxinia,  Amaryllis, 
Bomarea,  Griffinia,  and  many  others,  so  that  we  have  here  a 
curious  mixture  of  forest  trees  and  climbers  with  moisture- 
loving  plants  and  those  characteristic  of  arid  conditions,  all 
growing  close  together  if  not  actually  intermingled. 

Before  describing  a  few  of  the  special  peculiarities  of  the 
campo  vegetation  of  Lagoa  Santa,  I  will  here  give  some  numer- 
ical data  of  interest  to  botanical  readers.  The  sequence  of  the 
orders  in  this  very  interesting  flora  is  as  follows :  — 

Lagoa  Santa   (2490  species) 


1.  Compositae   26G 

2.  Leguminosae     235 

3.  Gramineae    158 

4.  Orchidaceae    120 

5.  Euphorbiaceae    100 

6.  Myrtacese  100 


7.  Rubiaceae    94 

8.  Cyperaceae    77 

0.  Malpighiaceap     04 

10.  INIelastomaceae 62 

1 1.  Labiatae    49 

12.  AsclepiadeiB 48 


Ferns  and  allies 106  species. 


72  THE  WORLD  OF  LIFE 

The  chief  feature  which  distinguishes  this  flora  from  that  of 
Nicaragua  and  Costa  Rica  is  the  presence  in  some  abundance 
of  the  highly  characteristic  South  ximerican  order  Malpighia- 
cese,  the  high  position  of  Myrtacese,  with  Labiates  and  Ascle- 
piads  in  place  of  Aroids  and  Palms.  Of  the  rather  numerous 
Orchids  about  70  are  terrestrial,  50  epiphytes.  There  are  over 
40  genera,  of  which  Spiranthes  has  16  species,  Habenaria  12, 
while  22  have  only  1  species  each.  The  very  large  American 
genus  Oncidium  has  only  5  species,  while  the  grand  genus 
Cattleya,  so  abundant  in  many  parts  of  Brazil,  seems  to  be 
entirely  absent. 

Adaptations  to  Brought 

The  plant  figured  on  the  next  page,  like  many  others  of  the 
campos,  has  its  roots  swollen  and  woody,  forming  a  store  of 
water  and  food  to  enable  it  to  withstand  the  effects  of  drought 
and  of  the  campo-fires.  The  old  stems  show  where  they  have 
been  burnt  off,  and  the  figures  of  many  other  plants  with  woody 
roots  or  tubers,  figured  by  Mr.  Warming,  show  similar  effects 
of  burning. 

Still  more  remarkable  is  the  tree  figured  on  p.  74  (Fig.  7), 
which  is  adapted  to  the  same  conditions  in  a  quite  different 
way,  as  are  many  other  quite  unrelated  species.-^  The  group 
of  plants  is  really  an  underground  tree,  and  not  merely  dwarf 
shrubs  as  they  at  first  appear  to  be.  What  look  like  surface- 
roots  are  really  the  branches  of  a  tree  the  trunk  of  which,  and 
often  a  large  part  of  the  limbs  and  branches,  are  buried  in 
the  earth.  The  stems  shown  are  the  root-like  branches,  which 
are  4—5  inches  diameter,  w^hile  the  growing  shoots  are  from 
2  to  3  feet  high.  The  whole  plan  (or  tree)  is  from  30  to  40 
feet  diameter.     As  the  branches  approach  the  centre  they  de- 

1  The  following  species  have  a  similar  mode  of  gro\vth :  Anacardium 
Jiumile,  Hortia  Brasiliensis  (Riitacese),  Cochlospermum  insigne  (Cistaceae), 
Simaha  Warniingiana  (Simariibaeese) ,  Erythroxylon  campestre  (Erythroxy- 
laceae),  Plumiera  Warmingii  ( Apocynaceae ) ,  Palicourea  rigida  (Cincho- 
naceae ) ,  etc. 


r. 

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TROPICAL  FLOEAS 


73 


Fig.  6. —  Casselia  Chamcedrifolia,  nat.  size   (Verbenacefie) . 

scend  into  the  earth   and   form   a  central  trunk.     A   French 
botanist,  M.  Emm.  Liais,  says  of  this  species:  "  If  we  dig  we 


74 


THE  WORLD  OF  LIFE 


find  liow  all  these  small  shrubs,  apparently  distinct,  are  joined 
together  underground  and  form  the  extremities  of  the  branches 
of  a  large  subterranean  tree  which  at  length  unite  to  form  a 
single  trunk.     M.  Eenault  of  Barbacena  told  me  that  he  had 


Fig.  7. —  Andira  Laurifolia   (Papilionacese). 

dug  about  20  feet  deep  to  obtain  one  of  these  trunks."  The 
large  subterranean  trees  with  a  trunk  hidden  in  the  soil  form 
one  of  the  most  singular  features  of  the  flora  of  these  campos 
of  Central  Brazil. 

The  above  facts  are  from  Mr.  Warming's  book,  supplemented 
by  some  details  in  a  letter.  They  are  certainly  very  remark- 
able ;  and  it  is  difficult  to  understand  how  this  mode  of  growth 
has  been  acquired,  or  how  the  seeds  get  so  deep  into  the 
ground  as  to  form  a  subterranean  trunk.  But  perhaps  the 
cracks  in  the  dry  season  explain  this. 

A  large  part  of  these  campos  is  burnt  every  year  at  the  end 
of  the  dry  season,  but  as  the  vegetation  is  scanty  the  fires  pass 


TKOPICAL  FLORAS  T5 

quickly  onwards  and  do  not  appear  to  kill  or  injure  the  trees 
or  even  the  small  herbaceous  plants.  In  fact,  numbers  of 
these  plants  as  soon  as  the  rains  come  produce  foliage  earlier 
than  Avhere  there  has  been  no  fire,  and  often  produce  flowers 
when  unburnt  trees  or  shrubs  of  the  same  species  remain 
flowerless.  Mr.  Warming  and  otlier  botanists  believe  that  the 
practice  of  firing  the  campos  was  a  native  one  long  before  the 
European  occupation,  and  that  many  of  the  plants  have  become 
adapted  to  this  annual  burning  so  as  to  benefit  by  it. 

It  is  interesting  to  note  here  the  opinions  of  two  eminent 
botanists,  only  thirty  years  ago,  as  to  the  comparative  riches 
of  certain  tropical  and  temperate  countries.  In  his  great  work 
on  The  Vegetation  of  the  Globe,  Griesbach  thus  refers  to  the 
Brazilian  flora :  ^^  The  results  of  the  explorations  of  Martins, 
Burchell,  and  Gardiner,  cannot  be  compared  with  those  fur- 
nished by  the  Cape.  The  number  of  endemic  species  may  per- 
haps reach  10,000,  but  the  area  is  twenty  times  greater  than 
that  of  Cape  Colony,  and  we  may  conclude  that,  as  regards  its 
botanical  riches,  the  Brazilian  flora  is  very  far  from  rivalling 
that  of  the  extremity  of  South  Africa."  Gardiner,  however, 
after  spending  three  years  in  collecting  over  a  large  portion 
of  the  interior  of  Brazil,  though  chiefly  in  the  campos  and 
mountain  ranges,  concludes  his  account  of  his  travels  with  these 
w^ords :  "  The  countrv  is  beautiful,  and  richer  than  anv  other 
in  the  world  in  plants."  This  general  statement  may  not  be 
strictly  true,  but  it  seems  clear  that  the  facts  already  adduced 
are  sufficient  to  show  that,  as  regards  the  comparison  of  tem- 
perate with  tropical  floras,  there  can  be  no  doubt  as  to  the 
superiority  of  the  latter.  This  point  will,  I  think,  l)e  made 
still  clearer  in  the  following  discussion  of  some  almost  unno- 
ticed facts.  In  the  case  of  Brazil  and  Cape  Colony,  however, 
it  is  clear  that  Griesbach  was  creatlv  in  error.  Tlie  wliole 
area  of  extra-tropical  South  Africa  has  probably  been  as  well 
explored  botanically  as  Brazil,  the  richest  portions  of  which 
have  been  only  as  it  were  sampled.  Yet  wo  find  less  than 
14,000  species  in  the  former  against  22,S00  in  the  latter.     It 


76  THE  WOELD  OF  LIFE 

will  be  now  shown  that  when  smaller  and  better  known  areas 
are  compared  the  superiority  of  the  tropics  is  more  clearly 
apparent. 

The  Floras  of  Small  Areas  and  their  Teachings 

The  conclusions  already  reached  by  the  examination  of  the 
chief  floras  of  the  world,  whether  in  areas  of  continental  extent, 
or  in  those  more  approaching  to  the  average  of  our  counties, 
that,  other  things  being  equal  or  approximately  so,  the  tropics 
are  far  more  prolific  in  species,  will  receive  further  confirma- 
tion, and  I  think  demonstration,  from  data  I  have  collected 
as  to  the  botanical  richness  of  much  smaller  areas,  which  having 
been  more  thoroughly  explored  afford  more  reliable  evidence. 
They  also  afford  very  suggestive  facts  as  to  the  best  mode  of 
future  exploration  which  may  enable  us  to  arrive  at  a  fair 
approximation  as  to  the  total  world-population  of  flowering 
plants. 

For  the  convenience  of  readers  I  give  here  two  tables  I 
have  prepared  of  the  floras  of  small  areas  in  tropical  and  tem- 
perate zones,  each  arranged  in  the  order  of  their  area  in  square 
miles  for  convenience  of  reference  and  comparison. 

I  will  now  briefly  discuss  the  various  interesting  questions 
raised  by  a  consideration  of  these  tables. 

It  is,  I  believe,  still  a  very  common  opinion  among  botanists 
that  the  wonderfully  diversified  flora  of  the  Cape  Region  of 
South  Africa  is  the  richest  in  the  whole  world  in  so  limited 
an  area.  This  is  partly  owing  to  the  fact  that  such  a  large 
proportion  are  beautiful  garden  plants,  which  for  sixty  years, 
from  1775  to  1835,  j^oured  in  a  continued  stream  into  Europe 
and  seemed  almost  inexhaustible.  The  wonderful  group  of 
heaths,  of  which  there  are  about  350  species,  all  beautiful  and 
many  among  the  most  exquisite  of  flowers ;  the  almost  equally 
numerous  pelargoniums,  the  brilliant  ixias,  gladioli  and  allies, 
the  gorgeous  proteas,  the  w^onderful  silver-tree,  the  splendid 
lilies  and  curious  orchises,  the  endless  variety  of  leguminous 
shrubs,  and  the  composites  including  the  everlasting  flowers. 


TEOPICAL  FLORAS 


77 


Tropical  Floras  —  Small  Areas 


Place. 


1 
2 
3 
4 
5 
6 


Malacca     

Singapore   

Penang    

Lagoa  Santa,  Brazil 

Mount    Pangerango,    Java 
Kambangan    Island,    Java 


Area. 

Species. 

660 

2000 

206 

1740 

107 

1813 

66 

2488 

n 

1750 

n 

2400 

Authoritj'. 


Gamble. 

Ridley. 

Curtis. 

Warming. 

Koorders. 

Koorders. 


Temperate  Floras  —  Smalt.  Areas 


1 
2 

3 
4 
5 
6 
7 
8 
9 
10 


Place. 


Mount   Nikko,    Japan .... 

Cape    Peninsula 

Schaffhausen    

Washington,    D.C 

Hertford     ( near ) 

Paramatta   River,   Sydney 

Capri,    Italy 

Edmondsham,  Dorset 

Cadney,  Lines 

Tliames   Ditton 


Area. 

Species. 

360 

800 

180 

1750 

114 

1020 

108 

922 

80 

810 

20 

620 

4 

719 

3 

640 

3 

720 

1 

400 

Authority, 


Havati. 

Bolus. 

A.   de  Candolle. 

Ward. 

A.  de  Candolle. 

H.  Deane. 

Beguinot. 

Rev.  E.  F.  Linton. 

Rev.    Woodruffe-Peacock. 

H.  C.  Watson. 


together  with  hundreds  of  other  delicate  and  beautiful  little 
greenhouse  plants, —  formed  an  assemblage  which  no  other 
country  could  approach.  Rich  as  it  is,  however,  there  is  now 
reason  to  believe  that  West  Australia  —  Swan  River  Colony 
in  its  original  restricted  sense  —  is  quite  as  productive  in  spe- 
cies, while  evidence  is  slowly  accumulating  that  many  parts 
of  the  tropics  are  really  still  more  productive. 

The  first  to  be  noticed  of  these  rich  tropical  areas  of  small 
extent  is  the  island  of  Penang  in  the  Straits  of  Malacca,  which, 
though  only  106  square  miles  in  area,  contains  1813  species. 
Sir  Joseph  D.  Hooker,  in  his  Sketch  of  the  Flora  of  British 
India  (1906),  terms  this  "  an  astonishing  number  of  species," 
and  remarks  on  the  large  proportion  which  are  arboreous,  and 
of  the  altitude  of  the  island  being  only  2750  feet.     TTere,  there- 


78  THE  WOKLD  OF  LIFE 

fore,  in  an  area  considerably  less  than  that  of  the  Cape  Pen- 
insula, the  species  are  actually  more  numerous,  and  this  was 
evidently  a  new  and  astonishing  fact  to  one  of  the  greatest  of 
our  living  botanists. 

But  the  somewhat  larger  island  of  Singapore  shows  us  that 
this  amount  of  productiveness  is  quite  normal;  for  though  it  is 
206  square  miles  in  extent,  it  is  almost  flat,  the  greatest  eleva- 
tion being  only  a  few  hundred  feet.  A  large  part  of  the  sur- 
face is  occupied  by  the  town  and  suburbs,  while  the  original 
forest  that  covered  it  has  been  almost  all  destroved.  Yet  Mr. 
Ridley  finds  it  to  have  recently  contained  1740  species,  and 
when  the  town  was  founded  and  the  forest  untouched,  it  almost 
certainly  had  2000  or  even  more. 

We  have  seen  also  that  Lagoa  Santa  in  South  Brazil, 
2700  feet  above  sea-level,  with  a  much  smaller  area  than 
Penang,  and  a  much  less  favourable  climate,  has  one-third 
more  species,  mainly  collected  by  one  enthusiastic  botanist 
during  three  years'  work  in  this  limited  district.  Here  are  no 
mountains,  the  whole  country  being  an  undulating  plateau, 
while  for  six  months  there  is  so  little  rain  that  the  trees 
almost  all  lose  their  leaves.  The  aridity  causes  the  trees  to 
be  mostly  stunted  and  unshapely;  the  leaves  are  clothed  on 
one  or  both  surfaces  with  felt  or  dense  hairs;  and  the  stems 
of  herbaceous  plants  are  often  swollen  into  thick  tubers 
either  underground  or  just  above  it.  There  is  thus  a  mani- 
fest struggle  for  existence  ajrainst  the  summer  drought  with 
intense  sun-heat,  and  it  would  hardly  be  imagined  that  under 
such  conditions  the  number  of  species  would  equal  or  exceed 
that  of  some  of  the  most  luxuriant  parts  of  the  tropics. 

I  will  now  pass  on  to  a  consideration  of  the  two  last 
items  in  the  table  of  small  tropical  floras,  which  are  more 
instructive  and  even  amazing  than  any  I  have  met  with  in 
the  course  of  this  inquiry.  "\^^ien  I  was  in  Java  about  fifty 
years  ago  I  ascended  the  celebrated  mountains  Gede  and 
Pangerango,  the  former  an  active,  and  the  latter,  much  the 
higher,    an    extinct    volcano.      The    two,    however,    form    one 


TROPICAL  FLORAS  T9 

mountain  with  two  summits.  During  the  ascent  I  was  much 
impressed  by  the  extreme  hixuriance  of  the  forest-growth,  and 
especially  of  the  undergrowth  of  ferns  and  herbaceous  plants. 
I  was  told  by  the  gardener  in  charge  of  the  nursery  of 
cinchonas  and  other  plants,  that  300  species  of  ferns  had  been 
found  on  this  mountain,  and  I  think  500  orchids.  I  was 
therefore  anxious  to  learn  if  any  figures  for  the  plants  of 
the  whole  mountain  could  be  obtained,  and  was  advised  by 
the  Director  of  Kew  Gardens  to  apply  to  Dr.  S.  Koorders  of 
the  Reijks  Museum,  Leiden.  In  reply  to  my  inquiries,  Dr. 
Koorders  wrote  me  as  follows :  — 

"The  botanical  mountain-reserve  on  the  Gede  (Pangerango)  is 
indeed  very  interesting  and  very  rich,  but  I  know  other  parts  of 
Java  with  a  much  larger  number  of  phanerogams,  e.  g.,  the  small 
island  of  Xoesa  Kambangan  near  Tjilatjap.  On  that  island  I 
collected  on  an  area  of  about  3  square  kilometres  (=  1%  square 
mile)  600  of  arborescent  species  of  phanerogams,  and  about  1800 
species  of  not-arborescent  species.  This  island  is  about  0  —  50  m. 
altitude  (=164  feet).'' 

"  On  Mount  Pangerango,  between  5350  feet  and  the  top,  10,000 
feet,  the  number  of  forest-trees  is  about  350  species  on  the  same 
area,  and  about  1400  species  of  not-arborescent  phanerogams." 

On  reading  the  above,  I  thought  at  first  that  Dr.  Koorders 
must  have  made  a  mistake,  and  have  meant  to  write  30  in- 
stead of  3  square  kilometres.  So  I  wrote  to  him  again  ask- 
ing for  some  further  information,  and  pointing  out  that 
Kambangan  Island  was  many  times  larger  than  the  area  he 
had  given.  To  this  he  replied  that  he  "  only  explored  a  small 
part  methodically,"  and  that  the  number  of  species  he  gave 
me  '^  were  found  in  that  part  only."  ^     It  thus  became  clear 

1  It  may  seem  to  some  readers,  as  it  did  at  first  to  myself,  that  it  is  im- 
possible to  have  over  two  thousand  species  of  flowering  plants  growing 
naturally  on  about  a  square  mile.  But  a  little  consideration  will  show 
that  it  is  by  no  means  so  extraordinary  as  it  seems.  Let  us  suppose  that 
the  average  distance  apart  of  trees  in  an  equatorial  forest  is  ten  yards, 
which  I  think  is  much  more  than  the  average;  then  in  a  square  mile  there 
will  be  176  X  170  =  30,976  trees.     But  in  Kambangan  Island  there  are  600 


80  THE  WORLD  OF  LIFE 

that  no  mistake  had  been  made.  I  was  further  satisfied  of 
this  bj  referring  to  a  small  volume  by  M.  Jean  Massart,  en- 
titled Un  Botaniste  en  Malaisie.  He  there  describes  the 
^'  mountain  reserA'e  "  on  Pangerango  as  being  300  hectares  of 
virgin  forest,  extending  from  the  limits  of  cultivation  to  near 
the  summit.  As  ''  300  hectares "  is  the  same  area  as  ''  3 
square  kilometres/'  there  can  be  no  doubt  as  to  the  figures 
given.  M.  Massart  also  states  that  Dr.  Koorders  was  head 
of  the  "  forest-fiora  "  department  of  the  Buitenzorg  Botanical 
Gardens,  and  that  he  had  established  eighteen  other  reserves 
in  various  regions  of  Java.  Each  of  these  reserves  is  under 
a  native  superintendent,  who  allows  no  tree  to  be  cut  down 
without  orders,  and  watches  for  the  flowering  and  fruiting  of 
every  species  of  tree.  One  specimen  at  least  of  all  the  species 
is  numbered,  and  paths  made  and  kept  in  order,  so  that  they 
can  be  easily  visited,  and  the  flowers  or  fruit  gathered  for  the 
herbarium.  Dr.  Koorders  has  now  obtained  specimens  of 
about  1200  trees  indigenous  to  Java,  while  3500  specimens 
have  been  numbered  in  the  reserves.  This  number  is  without 
counting  either  shrubs  or  climbers. 

I  give  here  a  reproduction  of  a  charming  little  photo- 
graph taken  in  West  Java  more  than  fifty  years  ago  by  my 
friend,  the  late  Walter  Woodbury,  and  I  believe  in  the  south- 
ern country  not  very  far  from  the  island  which  Dr.  Koorders 
found  so  rich  (Fig.  8).  The  intermingling  of  dwarf  palms 
and  ferns,  with  the  varied  foliage  of  shrubs  and  herbaceous 
plants,  and  the  abundance  of  lianas  hanging  everywhere  from 
the  trees  overhead,  give  an  impression  of  tropical  luxuriance 
beyond  even  that  of  the  Malayan  photographs  pp.  48  and  49. 

The  system  of  small  forest  reserves  in  tropical  or  other  im- 

species  of  trees  in  IJ  square  mile,  so  that  each  species  would  be  represented 
on  the  average  by  60  individuals.  But,  as  some  are  comparatively  common, 
others  rare,  there  would  in  some  cases  be  only  3  or  4  specimens,  while  many, 
having  from  50  to  100,  would  be  really  abundant,  but,  if  fairly  scattered 
over  the  whole  area,  even  these  might  require  searching  for  to  find  two  or 
three  specimens;  which  accords  with  the  facts  as  testified  by  all  botanical 
travellers. 


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TEOPICAL  FLORAS  81 

perfectly  known  countries  seems  to  ine  to  offer  so  many  ad- 
vantages that  the  adoption  of  it  in  Java  by  the  Dutch  botanists 
must,  I  think,  be  looked  upon  as  an  important  discovery.  It 
has  the  great  advantage  of  being  at  once  economical  and  ef- 
fective; it  brings  about  the  maximum  of  scientific  result  with 
the  minimum  of  cost,  of  time  and  of  labour.  It  has  proved 
that  the  careful  and  systematic  study  of  very  small  areas  is 
calculated  to  extend  our  knowledge  of  the  vast  world  of  plant- 
life  more  than  any  other  that  has  hitherto  been  adopted.  The 
plan  is  to  have,  in  any  extensive  country  or  island,  a  suit- 
able number  of  what  may  be  termed  "  botanical  reserves " 
(but  which  wdll  also  serve  as  zoological  reserv^es,  especially  for 
bird  and  insect  life)  ;  these  to  be  of  small  size,  say  one  square 
mile  each,  to  be  kept  absolutely  in  a  state  of  nature,  except 
the  provision  of  numerous  paths  giving  access  to  at  least  one 
specimen  of  every  species  of  tree  the  reserve  contains.  Ex- 
perience in  Java  seems  to  show  that  one  man,  or  two  if 
necessary,  can  keep  the  paths  open,  watch  for  the  flowering 
and  fruiting  of  trees,  gather  and  send  specimens  to  the  head 
of  the  department,  and  also,  I  presume,  serve  as  guide  to  any 
botanical  visitors  to  the  reserve.  But  when  the  trees  had  been 
all  found,  numbered,  and  named,  the  same  superintendent 
or  keeper  would  have  time  and  opportunity  for  the  collec- 
tion of  specimens  of  all  the  shrubs,  climbers,  epiphytes,  and 
herbs  that  grew  in  the  reserve,  identifying  the  place  of  all 
the  rarer  species  by  direction  and  distance  from  the  nearest 
named  tree,  the  epiphytes,  orchids,  ferns,  mosses,  etc.,  being 
identified  by  the  tree  they  grew  upon  being  numbered,  and 
made  accessible  by  a  path.  Of  course  this  area  of  3  square 
kilometres,  or  about  a  square  mile,  may  not  be  in  all 
cases  sufficient,  but  it  seems  likely  to  be  the  most  suitable  for 
luxuriant  tropical  forests.  In  more  open  country,  as  at 
Campo  Santo,  a  space  of  from  10  to  50  square  miles  might 
be  advisable,  because  the  trees  on  such  an  area  might  be  as 
easilv  found  as  in  a  mile  of  unbroken  forest,  and  w^ould  not 
be  much  more  numerous.     In   any  new   tropical   country   of 


82  THE  WOKLD  OF  LIFE 

Avhicli  ^ve  obtain  possession,  or  where  there  are  still  large  areas 
of  virgin  forest,  it  would  be  advisable  to  reserve  one  square 
mile  in  each  square  degree,  say  one  in  every  5000  square 
miles. 

There  are  many  incidental  advantages  in  this  thorough  de- 
termination of  the  plants  growing  on  a  definite  if  small  area 
over  that  which  has  usually  been  adopted  of,  as  it  were,  skim- 
ming the  cream  of  the  flora  of  enormous  areas,  such  as  most 
of  our  botanical  collectors  have  been  obliged  to  adopt.  The 
first  advantage  is  that  the  census  of  species  in  each  of  the 
reserved  areas  can  be  easily  made  exhaustive,  and  therefore 
comparable  with  other  similar  reserves.  Then,  when  a  few 
well-chosen  "  reserves "  are  similarly  treated,  the  change  of 
species  in  each  degree  of  latitude  and  longitude  can  also  be 
determined  with  considerable  accuracv.  In  like  manner  the 
change  of  species  for  each  1000  or  500  feet  of  elevation  can 
also  be  found.  Again,  the  proportion  of  forest  trees  to  the 
whole  of  the  flowering  plants  in  each  locality  will  enable  the 
whole  flora  of  a  large  district  to  be  determined  as  to  numbers 
by  ascertaining  the  number  of  species  of  trees  only  in  a  few 
small  areas. 

As  an  illustration  of  this  mode  of  computation  Dr.  Koorders 
has  found  that  on  the  Pangerango  mountain  the  trees  form 
one-fifth  of  the  whole  flora,  while  on  Kambangan  Island  they 
form  one-fourth.  If  there  are,  as  Dr.  Koorders  tells  me, 
about  1200  species  of  trees  actually  found  in  Java,  and  if, 
on  account  of  the  eastern  part  of  the  island  having  much  less 
lowland  forest,  we  take  one-fifth  as  the  more  probable  pro- 
portion for  the  whole,  then  the  flora  of  Java  may  be  estimated 
at  a  minimum  of  6000  species;  and  if  the  number  of  the 
trees  is  found  to  be  greater,  then  at  a  proportionately  higher 
number.  Hence  it  is  very  important  that  in  each  local  flora 
the  number  of  its  trees,  shrubs,  and  herbs  should  be  separately 
given.  It  appears  that  a  forest  reserve  of  17  square  miles 
has  been  established  on  the  Bay  of  Manilla ;  but,  as  it  is  as 
yet  very   imperfectly   explored,   it  would   be   more   useful   to 


TROPICAL  FLORAS  83 

thoroughly  explore  two  or  three  well-chosen  areas  of  one  square 
luilo  each. 

It  is  really  deplorable  that  in  so  many  of  our  tropical  de- 
pendencies no  attempt  has  been  made  to  preserve  for  posterity 
any  adequate  portions  of  the  native  vegetation,  especially  of 
the  virgin  forests.  As  an  example,  the  island  of  Singapore 
was  wholly  covered  with  grand  virgin  forest  at  the  begin- 
ning of  last  century.  When  I  was  there  in  1851  the  greater 
part  of  it  was  still  forest,  but  timber-cutting  and  clearing 
for  gambir  and  other  plantations  has  gone  on  without  restric- 
tion till  there  is  now  hardly  any  true  virgin  forest  left ;  and 
quite  recently  the  finest  portion  left  has  been  allowed  to  be 
destroyed  by  a  contractor  in  order  to  get  gi-anite  for  harbour 
w^orks,  which  might  almost  as  easily  have  been  obtained  else- 
where. The  grand  forest  trees  were  actually  burnt  to  make 
way  for  the  granite  diggers ! 

Surely,  before  it  is  too  late,  our  Minister  for  the  Colonies 
should  be  urged  without  delay  to  give  stringent  orders  that 
in  all  the  protected  Malay  States,  in  British  Guiana,  Trinidad, 
Jamaica,  Ceylon,  Burma,  etc.,  a  suitable  provision  shall  be 
made  of  forest  or  mountain  ''  reserves,"  not  for  the  purpose 
of  forestry  and  timber-cutting  only,  but  in  order  to  preserve 
adequate  and  even  abundant  examples  of  those  most  glorious 
and  entrancing  features  of  our  earth,  its  native  forests,  woods, 
mountain  slopes,  and  alpine  pastures  in  every  country  under 
our  control.  It  is  not  only  our  duty  to  posterity  that  such 
reserves  should  be  made  for  the  purpose  of  enjoyment  and 
study  by  future  generations,  but  it  is  absolutely  necessary  in 
order  to  prevent  further  deterioration  of  the  climate  and  de- 
struction of  the  fertility  of  the  soil,  which  has  already  taken 
place  in  Ceylon  and  some  parts  of  India  to  a  most  deplorable 
extent.  For  this  end  not  only  must  timber-producing  forests 
of  an  ample  size  be  secured,  but  on  all  mountain  slopes  con- 
tinuous belts  of  at  least  400  or  500  yards  wade  should  be 
reserved  wherever  forests  still  exist,  or  where  they  have  been 
already  lost  be  reproduced  as  soon  as  possible,  so  as  to  form 


84  THE  WOKLD  OF  LIFE 

retainers  of  moisture  by  the  surface  vegetation,  checks  to 
evaporation  by  the  shade  of  the  trees,  guards  against  torrential 
rains,  mud  slides,  snow  slides  where  such  are  prevalent,  and 
protection  against  winds.  On  level  or  nearly  level  ground, 
where  such  varied  uses  would  not  be  required,  similar  belts 
at  greater  distances  apart  should  be  saved  for  local  uses  and 
amelioration  of  climate,  besides  "  botanical  reserves  "  of  ade- 
quate extent  to  give  a  representation  of  each  type  of  vege- 
tation in  the  country. 

I  would  also  strongly  urge  that,  in  all  countries  where  there 
are  still  vast  areas  of  tropical  forests,  as  in  British  Guiana, 
Burma,  etc.,  all  future  sales  or  concessions  of  land  for  any 
purpose  should  be  limited  to  belts  of  moderate  breadth,  say 
half  a  mile  or  less,  to  be  followed  by  a  belt  of  forest  of  the 
same  width;  and  further,  that  at  every  mile  or  half-mile, 
and  especially  where  streams  cross  the  belts,  transverse  patches 
of  forest,  from  one  to  two  furlongs  wide,  shall  be  reserved, 
to  remain  public  ]3roperty  and  to  be  utilised  in  the  public 
interest.  Thus  only  can  the  salubrity  and  general  amenity 
of  such  countries  be  handed  on  to  our  successors.  Of  course 
the  general  position  of  these  belts  and  clearings  should  be 
determined  by  local  conditions;  but  there  should  be  no  ex- 
ception to  the  rule  that  all  rivers  and  streams  except  the  very 
smallest  should  be  reserved  as  public  property  and  absolutely 
secured  against  pollution;  while  all  natural  features  of  es- 
pecial interest  or  beauty  should  also  be  maintained  for  public 
use  and  enjoyment. 

The  great  Eoraima  mountain  in  British  Guiana,  for  ex- 
ample, with  at  least  half  a  mile  of  forest  around  its  base, 
should,  so  far  as  w^e  are  possessors  of  it,  be  absolutely  se- 
cured; and  generally,  every  important  mountain  summit,  with 
ample  means  of  access,  should  also  be  reserved,  so  that  they 
may  not  be  monopolised  or  defaced  by  the  greed  of  specula- 
tive purchasers.  It  should  always  be  kept  in  mind  that  the 
reckless  clearing  of  large  forest-areas,  especially  in  the  tropics, 
produces  devastation  which  can  never  be  repaired.     It  leads 


TROPICAL  FLORAS  85 

to  the  denudation  of  the  rich  surface  soil  bj  torrential  rains ; 
this  soil  has  been  produced  by  countless  ages  of  forest  growth, 
and  it  will  require  an  equal  lapse  of  time  to  reproduce  it. 

Returning  now  to  the  more  direct  teachings  of  small  areas 
when  methodically  studied,  I  may  add  that  Dr.  Koorders  has 
informed  me  that  some  years  since  he  made  a  visit  to 
Minahassa,  in  X.  Celebes,  and  in  four  months,  between  the 
sea-level  and  6500  feet,  he  collected  or  observed  about  2000 
species  of  flowering  plants,  of  wdiich  about  700  were  forest 
trees.  As  these  last  are  Dr.  Koorders'  special  study  it  is 
to  be  presumed  he  paid  great  attention  to  them,  yet  he  could 
hardly  have  obtained  such  a  complete  knowledge  of  them  in 
a  few  months  as  in  the  ^'  reserves "  of  Java,  where,  in  suc- 
cessive years,  not  a  single  species  could  have  escaped  dis- 
covery. This  would  imply  that  the  forest  flora  of  Xorth 
Celebes  is  even  richer  than  that  of  Java,  and  it  is  almost 
certainly  more  peculiar.  And  if  the  larger  islands  of  the 
Moluccas  —  Gilolo,  Batchian,  and  Ceram  —  are  equally  rich 
(and  they  have  all  the  appearance  of  being  so),  then  every 
estimate  yet  made  of  the  species-population  of  the  whole 
Archipelago  must  be  very  far  below  the  actual  numbers. 

There  must  be  hundreds  of  young  botanists  in  Europe  and 
America  who  w^ould  be  glad  to  go  to  collect,  say  for  three 
years,  in  any  of  these  islands  if  their  expenses  were  paid. 
There  would  be  work  for  fifty  of  them,  and  if  they  were  prop- 
erly distributed  over  the  islands  from  Sumatra  to  Xew  Guinea 
in  places  decided  upon  by  a  committee  of  botanists  who  knew 
the  country,  with  instructions  to  limit  their  work  to  a  small 
area  which  they  could  examine  thoroughly,  to  make  forest 
trees  their  main  object,  but  obtain  all  other  flowering  plants 
they  met  with,  a  more  thorough  and  useful  botanical  explora- 
tion Avould  be  the  result  than  the  labours  of  all  other  col- 
lectors in  the  same  area  have  accomplished,  or  are  likely  to 
accomplish,  during  the  next  century.  And  if  each  of  these 
collectors  had  a  moderate  salary  for  another  three  years  in 
order  to  describe   and   publi^^h   the   results   of  their  combined 


8Q  THE  WORLD  OF  LIFE 

work  on  a  uniform  plan,  and  in  a  cheap  form,  the  total  ex- 
pense for  all  the  nations  of  Europe  combined  would  be  a 
mere  trifle.  Here  is  a  great  opportunity  for  some  of  our 
millionaires  to  carry  out  this  important  scientific  exploration 
before  these  glorious  forests  are  recklessly  diminished  or 
destroyed  —  a  work  which  would  be  sure  to  lead  to  the  dis- 
covery of  great  numbers  of  plants  of  utility  or  beauty,  and 
would  besides  form  a  basis  of  knowledge  from  which  it  woukl 
be  possible  to  approach  the  various  great  governments  urging 
the  establishment,  as  a  permanent  possession  for  humanity,  of 
an  adequate  number  of  such  botanical,  or  rather  biological, 
^'  reserves ''  as  I  have  here  suggested  in  every  part  of  the 
world. 

Before  leaving  the  very  interesting  problems  suggested  by 
the  floras  of  ''  small  areas,"  I  will  point  out  that  in  the  tropics, 
in  warm  temperate  and  in  cool  temperate  zones  alike,  the  evi- 
dence goes  to  show  that  mountain  floras  are  not  so  rich  in 
species  as  those  of  the  plains.  I  have  already  shown  that  it 
is  the  case  in  our  own  islands,  in  Switzerland  and  in  South 
Euroj^e.  The  table  of  extra-European  small  areas  (p.  40) 
shows  that  the  gTeat  Japanese  mountain,  Fujiyama,  with  a 
larger  area  and  an  altitude  of  over  12,000  feet,  has  a  smaller 
number  of  species  than  Mt.  Kikko,  with  a  smaller  area  and 
an  altitude  of  only  8000  feet,  both  mountains  being  cultivated 
to  the  same  height  (800  feet),  and  both  being  equally  well 
explored.  And  now,  coming  to  the  tropics,  we  find  in  Java 
two  areas  of  the  same  extent  and  fullv  explored  bv  the  same 
botanist,  one  on  a  grand  mountain  slope  from  4500  to  0500 
feet,  and  celebrated  for  its  rich  flora,  the  other  at  the  sea- 
level,  and  the  latter  is  decidedly  the  richest.  Yet  we  find 
Gardiner,  in  his  Travels  in  Brazil,  taking  the  very  opposite 
of  this  for  granted.  He  says,  at  the  end  of  his  Avork :  ''  Xo 
good  reason  has  yet  been  suggested  to  account  for  the  greater 
number  of  species  which  exist  on  a  given  space  on  a  mountain 
than  on  a  plain."     The  answer  seems  to  be  that  there  is  no 


TROPICAL  FLORiVS  87 

such  general  fact  to  be  explained.  There  may  often,  no  doubt, 
be  more  plants  on  some  mountains  than  on  the  adjacent  plains, 
especially  on  open  plains  where  social  plants  abound.  On 
mountains  the  botanist  can  often  collect  more  species  in  the 
same  time,  because  diversities  of  soil  and  station  are  more 
crowded  together,  but  the  accurate  determination  of  the  species 
on  areas  from  one  square  mile  up  to  some  hundreds  of  miles 
shows  that  the  fact  is  almost  uniformly  the  other  way. 

It  is  also  of  special  interest  to  note  that  the  well-known 
fact  in  our  own  country,  that  a  parish  of  2  or  3  square  miles 
in  area  often  contains  more  than  half  the  flora  of  the  whole 
county  many  hundred  times  as  great  (as  in  the  cases  of  Cad- 
ney,  Edmondsham,  and  Thames  Ditton,  given  in  the  table), 
appears  to  be  even  exaggerated  in  the  more  luxuriant  tropical 
forests,  where  a  single  square  mile  often  contains  as  many 
species  as  100  miles  in  similar  forests  elsewhere. 

It  is,  however,  interesting  to  note  that  when  we  compare 
very  small  areas,  measured  by  feet  or  yards  instead  of  by 
square  miles,  it  is  the  temperate  floras  which  seem  to  have 
a  decided  advantage.  Darwin  records  that  on  a  piece  of  turf 
3  feet  X  4  feet  long  exposed  to  uniform  conditions,  (prob- 
ably on  the  chalk  downs  of  Kent  or  the  Isle  of  Wight)  he 
found  twentj"  species  of  plants  belonging  to  eighteen  genera 
(Origin  of  Species,  6th  ed.  p.  88).  Sir  Joseph  Hooker  in 
the  Himalayas,  11,480  feet  above  the  sea,  in  the  upper  Lachen 
valley,  found  a  much  richer  vegetation.  He  says :  ^^  Herba- 
ceous plants  are  much  more  numerous  here  than  in  any  other 
part  of  Sikhim;  and  sitting  at  my  tent  door  I  could,  without 
rising  from  the  ground,  gather  forty-three  plants,  of  which 
all  but  two  belonged  to  English  genera."  And  in  a  note  ho 
adds :  "  In  England  thirty  is  on  the  average  the  equivalent 
number  of  plants  which  in  favourable  localities  I  have 
gathered  in  an  equal  area."  ^ 

In  my  limited  reading  I  have  found  no  other  reference  to 
this  form  of  species-abundance,  nor  do  any  of  my  botanical 
I  Himalayan  Journals    (olieap  ed.),  p.  335, 


88  THE  WOELD  OE  LIFE 

friends  appear  to  have  recorded  such;  hut  it  Avould  be  inter- 
esting to  know  if  any  parts  of  Switzerland  or  the  Pyrenees 
were  as  rich  as  the  Himalayas.  I  should  expect  not,  as  the 
latter  has  a  great  advantage  in  area,  and  also  I  presume  in 
climate.  The  snow  protection  in  winter  would  be  similar, 
but  I  presume  the  summer  would  be  somewhat  longer  and  the 
temperature  more  equable,  while  the  more  nearly  vertical  sun 
and  much  greater  rainfall  would  probably  lead  to  a  more 
luxuriant  development  of  species  than  in  higher  latitudes,  or 
less  elevated  stations.  Darwin  points  out  that  the  produc- 
tion of  short  velvety  flower-decked  turf  depends  entirely  on 
its  being  regularly  cropped  down  by  ruminants,  preventing 
the  more  delicate  plants  from  being  smothered  by  the  coarser. 
Now,  this  group  of  animals  is  one  of  the  latest  developments 
of  the  world  of  life;  and  we  thus  learn  that  these  delight- 
ful expenses  of  flower-enamelled  turf  are  actually  produced  by 
the  sheep  or  goats,  the  deer  or  antelopes  whose  presence  gives 
them  a  further  charm,  and  which  were  themselves  developed 
just  at  the  period  when  man  appeared  upon  the  earth,  gifted 
with  faculties  which  enables  him  alone  to  fully  appreciate 
their  beauty,  and  to  utilise  many  of  them  as  aids  to  his  own 
civilisation. 


CHAP TEE  y 

THE  DISTEIBUTIOiq^  OF  ANIMALS 

The  sketch  now  given  of  the  broader  features  of  the  distribu- 
tion of  plants  over  the  various  parts  of  the  earth's  surface 
will  apply,  with  little  modification,  to  the  various  classes  of  ani- 
mal life,  which,  although  having  the  power  of  locomotion,  are  yet 
by  the  necessity  of  acquiring  food  and  preserving  themselves 
from  enemies,  almost  as  strictly  limited  to  definite  areas  as 
are  plants  themselves. 

It  will  only  be  necessary  to  give  a  few  facts  to  illustrate 
this,  for  which  purpose  insects  and  birds  afford  the  most  in- 
structive materials.  We  will  begin  with  the  Lepidoptera,  or 
Butterflies  and  Moths,  in  our  own  country  and  in  a  typical 
county.  The  following  data  have  been  kindly  furnished  by 
Mr.  William  Cole,  F.L.S.,  Hon.  Sec.  of  the  Essex  Eield 
Club. 

Distribution  of  Lepidoptera 

Sq^Mfles.  ^^''''''• 

Great   Britain 87,500  2070 

Essex 1,530  1655 

In  order  to  compare  the  numbers  in  a  smaller  area,  I  have 
only  materials  for  the  Macrolepidoptera  or  Butterflies  and 
larger  Moths. 

Sq^MHes.  ^^'''''■ 

Great    Britain 87,500  822 

Essex 1,530  620 

Epping  Forest 10  428 

It  is  interesting  to  note  here  the  curious  correspondence 
with  the  number  of  the  flowering  plants,  which  in  the  mean 
of  twelve  counties  was  almost  tlio  same  as  the  area  in  miles; 

89 


90  THE  WORLD  OF  LIFE 

and  here  we  find  the  total  number  of  the  Lepidoptera  in 
Essex,  which  is  not  far  from  an  average  county,  very  nearly 
the  same  as  its  area.  The  number  of  species  of  these  insects 
is  also  suggestive,  in  being  about  one-half  greater  than  the 
number  of  flowering  plants  (1010)  on  which  they  almost  all 
feed  in  their  larval  state.  We  know  that  many  different 
species  feed  on  some  of  our  commonest  plants  —  as  the  oak, 
poplar,  elm,  nettle,  etc. —  while  some  larv^^e  feed  on  several 
distinct  plants  indiscr,iminately.  But  probably  the  larger 
number  feed  on  one  species  of  plant  only,  and  thus  almost  all 
our  plants,  except  the  very  rarest,  afford  food  for  at  lea^t  one 
lepidopterous  larva. 

Again,  just  as  we  found  that  a  selected  area  of  10  square 
miles  in  Surrey  had  nearly  two-thirds  of  the  plants  in  the 
whole  county,  so  here  we  find  that  a  selected  area  of  10  square 
miles  in  Essex  has  nearly  two-thirds  of  the  Macrolepidoptera 
found  in  the  county.  Here,  too,  we  see  the  result  of  the  de- 
pendence of  the  insects  on  the  plants,  the  great  variety  of 
the  latter  in  Epping  Forest  (150  species)  rendering  possible 
a  corresponding  variety  of  the  former. 

Coleoptera   (Beetles) 

The  enormous  order  of  the  beetles  (Coleoptera)  not  being 
exclusively  feeders  on  living  plants,  but  both  in  their  larval 
and  perfect  state  often  feeding  on  animal  food  or  on  vege- 
table debris,  are  probably  more  uniform  in  their  numbers  in 
different  areas  if  not  absolutely  barren  or  very  highly  culti- 
vated. 

Area.  Species. 

Great   Britain 87,500  3260 

Essex     1,530  1655 

As  it  requires  perseverance  in  collecting  for  many  years 
in  order  to  obtain  all  the  beetles  in  even  a  very  limited 
district,  I  think  it  probable  that  the  above  figures  do  not  so 
closely  represent  the  actual  number  of  species  inhabiting  the 
county  as  in  those  given  for  the  plants,  or  even  the  moths. 


THE  DISTRIBUTION  OF  AOTMALS  91 

To  show  the  vast  numbers  and  variety  of  the  insect  tribes, 
I  give  here  the  approximate  numbers  of  actually  described 
insects,  kindly  furnished  me  by  Mr.  C.  O.  Waterhouse  of  the 
Entomological  Department  of  the  Natural  History  Museum. 

Insects  of  the  World.  Number  of   Described 

Species. 

Coleoptera   (Beetles) 120,000 

Lepidoptera  ( Moths  and  Butterflies ) 00,000 

Hymenoptera    (Bees,  Wasps,  Ants,  etc.) 45,000 

Diptera    (Flies,  Gnats,  Midges,  etc.) 28,000 

Rhynchota   (Bugs,  Cicadas,  etc.) 18,000 

Orthoptera   (Locusts,  Crickets,  etc.) 8,000 

Neuroptera    ( Dragon-flies,  May-flies,  etc. ) 5,000 

Several  smaller  Orders 5,000 

Land  Area,  48,000,000  square  miles 240,000 

I 

If  we  consider  that  large  areas  of  the  most  productive 
tropical  regions  are  still  almost  unexplored  by  the  ento- 
mologist, and  that  even  in  the  best-known  parts  the  less 
attractive  groups  are  very  little  known,  it  is  almost  certain 
that  the  actual  number  of  species  of  insects  now  in  existence 
is  double  that  above  given,  while  it  may  be  three  or  four 
times  as  many. 

To  show  how  difficult  it  is  to  ascertain  how  many  species 
of  insects  are  now  known  to  exist,  I  give  another  recent  esti- 
mate by  Mr.  A.  E.  Shipley,  F.  R.  S.,  in  his  Presidential 
Address  to  the  Zoological  Section  of  the  British  Association 
in  1909.  This  was  based  upon  a  careful  estimate  by  Dr. 
Giinther,  in  1881,  when  Keeper  of  Zoology  in  the  British 
^luseum.  His  estimate  then  was  220,150  species  of  insects. 
In  the  twenty-seven  succeeding  years,  the  7.ooJogical  Record 
gives  the  number  of  new  species  described  in  all  parts  of  the 
world.  During  the  whole  of  this  time  the  numbers  described 
have  increased  vear  bv  vear,  and  Air.  Shiplev  has  therefore 
taken  the  number  for  the  vear  1897  as  an  averaa'c  of  the 
wliole  (8364  n.s.),  and  multijdying  this  by  27  ('allowing  the 
odd  364  for  synonyms)  we  have  an  addition  of  216,000,  which 


92  THE  WOKLD  OF  LIFE 

added  to  220,000  gives  a  total  now  known  of  JfS6,000,  an 
immense  increase  on  the  estimate  of  Mr.  Waterhouse.  Of 
course  a  far  more  correct  way  would  be  to  add  the  number 
described  as  new,  each  year  of  the  twenty-seven;  but  as  this 
would  involve  the  counting  of  all  the  descriptions  in  thousands 
of  pages  of  close  print,  we  cannot  be  surprised  that  such  a 
labour  was  not  undertaken. 

It  is  hardly  possible  for  any  one  who  has  not  collected 
some  special  group  of  insects  in  countries  where  they  abound, 
to  realise  what  the  numbers  given  above  really  mean.  In 
the  Malay  Islands  alone,  I  myself  collected  over  a  thousand 
distinct  species  of  one  of  the  most  beautiful  families  of  beetles 
—  the  Longicorns  —  of  which  about  900  were  previously  quite 
unknown.  Of  another  immense  family  —  the  Curculionidge, 
or  Weevils  —  I  obtained  also  about  1000  species,  of  which  the 
same  proportion  were  new.  Wliile  the  former  group  are  re- 
markable for  grace  of  form,  variety  of  marking,  and  often  for 
exquisite  colouration,  the  latter  are  equally  interesting  for 
their  endless  modifications  of  shape,  more  sober  but  beauti- 
fully marked  bodies,  strangely  bossed  surfaces,  and,  occa- 
sionally, the  most  brilliant  metallic  colours. 

The  interest  of  making  such  collections,  in  which  the  variety 
was  so  great  as  to  seem  absolutely  endless,  may  be  imagined 
by  any  lover  of  nature.  But  the  interest  in  their  study  has 
been  intensified  by  the  firm  conviction  —  the  growth  of  half 
a  century  of  thought  upon  the  subject  —  that  every  detail  of 
these  wonderful  modifications  of  structure,  form,  and  coloura- 
tion, have  been  due  to  general  laws  in  operation  for  count- 
less ages,  and  that  every  minutest  character,  as  they  occurred 
through  successive  variations  and  became  fixed  in  each  species, 
had  a  definite  purpose;  that  is,  were  of  use  to  the  creatures 
which  exliibited  them.  This,  however,  will  be  shown  later 
on,  when  we  have  to  deal  with  the  more  important  factors 
of  evolution  —  variation  and  heredity. 


THE  DISTRIBUTION  OF  ANIMALS  93 

The  Species  of  Birds 

We  will  now  pass  on  to  the  most  familiar,  the  most  beauti- 
ful, and  the  most  wonderful  of  all  living  things  —  the  birds. 
These  form  one  of  the  culminating  lines  of  development  of 
the  great  world  of  life ;  they  are  the  most  specialised  of  all 
the  higher  animals ;  and  so  far  as  perfection  of  organised 
structure  is  concerned  may  be  considered  to  hold  a  higher 
place  than  the  mammals  themselves.  Were  they  not  so  familiar 
to  us,  we  should  consider  it  to  be  impossible  that  warm-blooded, 
active  creatures,  with  a  bony  skeleton,  could  have  their  fore- 
limbs  (or  arms)  so  modified  as  to  be  used  exclusively  for 
flight,  and  yet,  with  no  organ  of  prehension  but  the  mouth 
prolonged  into  a  beak,  sometimes  aided  by  a  foot,  be  completely 
adapted  to  obtain  every  kind  of  vegetable  or  animal  food,  to 
protect  themselves  from  enemies,  and  to  construct  the  most 
perfect  abodes  for  their  helpless  young  to  be  found  among  the 
higher  animals. 

Some  zoologists  consider  that  in  the  power  of  flight  birds 
are  surpassed  by  insects,  but  I  cannot  think  this  to  be  the 
case.  If  we  take  into  consideration  the  weight  they  have  to 
carry,  the  height  they  often  attain  above  the  earth,  their  per- 
fect command  over  the  direction  and  speed  of  their  motion, 
and  the  exquisite  and  highly  complex  organ  by  which  flight 
is  effected,  birds  must  take  the  higher  place.  The  insect's 
flight  is  simpler  and  more  automatic;  that  of  the  bird  more 
elaborate  in  every  part,  more  completely  under  the  control 
of  the  creature's  will.  It  is  also,  I  believe,  more  varied  in 
exact  adaptation  to  the  mode  of  life  of  each  of  the  species. 

As  regards  their  variety  of  structure,  the  numbers  of  the 
species,  and  their  mode  of  distribution  over  the  earth's  sur- 
face as  compared  with  the  other  forms  of  life  already  con- 
sidered, a  few  examples  will  be  sufficient  to  prove  their  general 
correspondence  with  other  animals.  It  must  be  remembered, 
however,  that  in  birds  the  numbers  inhabiting  the  several 
countries  are  less  precise  and  less  comparable  than  in  any  other 


94  THE  WORLD  OF  LIFE 

group.  This  is  due  to  several  causes.  In  all  extra-tropical 
lands  a  large  proportion  of  the  species  are  migratory,  and  the 
facts  observed  are  very  similar  over  the  whole  of  the  north 
temperate  zone.  Some  go  to  more  northern  lands  in  summer 
to  breed,  returning  south  in  autumn ;  others  leave  us  in  autumn 
to  winter  in  the  south,  returning  to  lis  in  the  spring;  others, 
again,  are  birds  of  passage  only,  staying  with  us  a  few  days 
or  weeks  on  their  way  north  or  south.  All  these  are  con- 
sidered to  be  truly  natives,  in  our  case  to  be  ^'  British  birds." 
But  others  only  visit  ns  occasionally,  some  at  very  long  inter- 
vals, while  others,  again,  are  mere  "  stragglers,"  who  have 
lost  their  way  or  been  driven  to  us  by  storms,  and  have  only 
perhaps  been  recorded  (seen  or  killed)  once  or  twice.  There 
is  therefore  a  vast  range  for  personal  opinion  as  to  what  species 
should  or  should  not  be  included  as  "  British  "  or  "  European  " 
or  '^  Canadian "  birds.  If  we  add  to  this  uncertainty  the 
extreme  variety  of  opinion  as  to  the  limits  of  ^'  species,"  "  sub- 
species," and  "  varieties,"  or  ^'  local  races "  of  birds  which 
now  exist,  we  see  how  hopeless  it  is  to  expect  uniformity  in 
numerical  estimates  of  the  birds  of  different  countries  or  re- 
gions. As  an  example  of  this  difference  of  treatment,  we  may 
take  two  of  the  most  recent  estimates  of  the  bird-population 
of  the  world.  Dr.  Glinther,  in  1881,  estimated  the  species 
of  birds  then  known  at  11,000,  and  Mr.  Shipley  added  to  this 
an  average  of  105  new  species  per  annum  —  estimated  from 
the  y.oological  Record  —  for  the  twenty-seven  years  elapsed 
since  that  date,  bringing  the  total  up  to  13,835.  But  in  the 
late  Dr.  Bowdler  Sharpens  Hand  List  of  the  Genera  and 
Species  of  Birds,  just  completed,  the  number  is  stated  as  being 
18,937.  This  enormous  divergence,  as  I  am  informed  by  an- 
other great  authority  on  Ornithology,  Dr.  P.  L.  Sclater,  is 
mainly,  if  not  wholly,  due  to  the  fact,  that  Dr.  Sharpe  '^  in- 
cludes as  species  all  the  numerous  slight  local  forms  which 
are  called  '  sub-species  '  by  the  new  school  of  Ornithologists, 
many  of  which,  in  my  opinion,  do  not  present  sufficient  dif- 
ferences to  require  separation  at  all." 


THE  DISTRTBUTIOIsr  OF  AXIMALS 


95 


Keeping  tlicse  difficulties  iu  mind,  the  following  estimates, 
for  which  I  am  largely  indebted  to  my  friend,  Mr.  Henry 
Dresser  (author  of  a  great  work  on  the  Birds  of  Europe),  will 


be  found  interesting. 


Species  of  Birds 


Square  Miles. 


Europe    

Great   Britain 
Dorset    


3,850,000 

87,000 

988 


Number  of  Species. 


770 
410 
2101 


Mansel-Pleydell's  Birds  of  Dorset. 

The  numbers  for  Dorset  are  obtained  by  omitting  all  the 
"  stragglers "  and  very  rare  visitors,  including  all  that  are 
regular  immigrants  or  birds  of  passage,  as  well  as  those  which, 
though  irregular,  are  tolerably  frequent  visitors.  Here,  again, 
we  see  that  a  county  area  has  rather  more  than  half  the 
British  species,  as  was  the  case  wdth  flowering  plants  and 
some  of  the  most  extensive  orders  of  insects. 

The  difficulty  of  obtaining  really  comparable  figures  for  the 
countries  and  regions  shown  on  page  96  is  at  present  insuper- 
able, but  the  approximations  given  are  of  considerable  interest. 

The  same  table  exhibits  several  points  of  interest,  espe- 
cially as  regards  the  correspondence  of  the  proportionate 
numbers  of  such  different  organisms  as  birds  and  plants.  As 
regards  the  Palsearctic  and  N^earctic  regions  (temperate 
Europe  and  Asia  on  the  one  hand,  temperate  North  Am.erica 
on  the  other),  we  see  that  the  birds  of  the  former  are  about 
one  and  a  half  times  those  of  the  latter,  the  areas  being  nearly 
as  two  to  one.  The  plants  are  probably  not  far  from  the 
same  proportion;  for  if  we  take  those  of  Europe  with  North 
Africa  at  10,000,  and  add  thereto  those  of  the  Flora  Orientalis 
of  Boissier  (12,000),  and  the  China  flora  of  Hemsley  (9000), 
and  allowing  that  the  species  common  to  any  two  of  these  may 


96 


THE  WOELD  OF  LIFE 


Table  of  the  Species  of  Birds 


Region  or  Country. 


Palaearctic  Region 

Nearctic  Region 

Ethiopian    Region 

Oriental  Region 

British  India 

Borneo 

Philippines   

Neotropical  Region 

Central  America  and 
South    Mexico 

Brazil     

Australian  Region 

Australia     

New  Guinea 


Area, 
Sq.  Miles. 


17,000,000 
8,000,000 
7,555,000 
3,350,000 

1,560,000 
297,000 
115,500 

7,590,000 

940,000 
3,288,000 
3,500,000 
3,009,000 

310,000 


Number 

of 
Species. 


1250 

760 

2490 

2300 

1617 
500 
700 

4100 

1300 
1568 

883 
950 


Dresser. 

Ridgway. 

Reichenow, 

Estimate. 

Dresser 

Ernst    Hartert    (1910) 


Biol.  Am.  Cent.  (1905), 
Von  Thering    (1907). 

E.  Hartert    (1908). 
Ernst  Hartert. 


The  numbers  for  the  Oriental  Region  have  been  estimated  on  the  method  of  Mr. 
Shipley  above  referred  to;  and  the  same  has  been  done  for  the  Neotropical  and 
Australian  Regions. 

The  numbers  for  Central  America  and  Mexico  have  been  reduced  from  those  of 
the  Biologia  Am.  Cent.,  because  that  work  includes  all  temperate  Mexico  with  a 
large  number  of  Nearctic  species. 

be  about  equal  to  additional  species  of  the  whole  of  N'orth 
Asia  and  Japan,  we  get  a  total  of  31,000  species,  which  is 
far  beyond  the  highest  estimate  of  the  Xearctic  flora  with  all 
the  sub-species  included. 

The  birds  of  the  Ethiopian  and  Oriental  Regions  appear 
to  be  approximately  equal  in  numbers.  The  flowering  plants 
are  even  less  known.  Those  of  tropical  Africa  with  Madagas- 
car, Mauritius,  etc.,  must  reach  about  22,000  species;  while 
temperate  South  Africa  has  13,000.  Allowing  the  species 
common  to  both  to  equal  those  yet  undescribed  from  tropical 
Africa,  we  get  a  total  of  35,000  species  for  the  Ethiopian 
flora. 

That  of  the  Oriental  Rei^ion  is  much  more  difficult  to  ar- 
rive  at.  Taking  15,000  species  for  the  tropical  portion  of 
the  flora  of  British  India,  and  addins:  7000  for  Indo-China, 


THE  DISTEIBUTIOX  OF  AXIMALS  97 

5000  for  the  Pliilippincs,  4000  fur  Java,  and  the  same  for 
additional  species  of  Makiysia  proper  (Malay  Peninsula, 
Borneo,  and  Sumatra),  and  2000  for  Celebes,  Ave  have  a  total 
of  30,000,  Avhich,  considering  that  the  land  area  of  this  region 
is  less  than  half  that  of  the  Ethiopian,  shows  Avhat  is  prob- 
ably a  fair  approximation  to  the  number  of  its  flowering 
plants;  though  I  believe  it  will  be  below  rather  than  above 
the  actual  amount. 

Coming  now  to  the  [N'eotropical  Region  (including  all  South 
America  and  tropical  Xorth  America),  we  find  our  estimate  of 
the  birds  to  be  almost  double  that  of  either  of  the  other  tropical 
regions.  By  means  of  a  rough  estimate  (p.  64)  I  have  arrived 
at  80,000  species  as  a  not  improbable  number  of  the  flower- 
ing plants  for  the  [N^eotropical  Region ;  and  allowing  fully  for 
future  discoveries  in  the  Malayan  Islands  and  Indo-China,  the 
numbers  in  the  Oriental  Region  are  not  likely  to  much  exceed 
half  this  number,  thus  agreeing  very  well  with  the  proportion- 
ate numbers  of  birds  in  the  same  regions. 

The  Australian  Region  is  of  less  importance  from  the 
point  of  view  we  are  now  considering,  because  it  is  not  ex- 
clusively temperate  or  tropical,  but  nearly  equally  divided  be- 
tween the  two.  It  also  differs  from  the  Oriental  inasmuch 
as  botanists  usually  claim  the  flora  of  the  Moluccas  and  Xew 
Guinea  as  being  essentially  Malayan,  and  therefore  belonging 
to  the  Oriental  Region.  But  the  flora  of  Xew  Guinea  has 
been  stated  by  Sir  Joseph  Hooker  to  be  so  peculiar  as  al- 
most to  deserve  to  form  a  Sub-region  of  its  own ;  and,  till 
recently,  the  natural  order  Dipteracese,  consisting  of  lofty 
forest-trees  with  very  distinctive  botanical  characters,  was 
supposed  to  be  limited  to  the  Oriental  Region,  from  the 
Himalayas  to  Java,  Celebes,  and  the  Philippines.  They  have, 
however,  now  been  found  both  in  the  ^Moluccas  and  Xew 
Guinea ;  but  as  westerly  winds  blow^  for  half  the  year  with 
great  steadiness  between  Celebes  and  Xew  Guinea,  it  is  not 
difficult  to  explain  their  presence  in  the  latter  country,  as  their 
solid  but  larire-winc-ed  fruits  would  be  easilv  drifted  for  lonff 


98  THE  WORLD  OF  LIFE 

distances.  At  all  events  the  extreme  richness  of  Xew  Guinea 
in  both  birds  and  plants,  and  not  improbably  in  insects  also, 
is  a  matter  of  very  great  interest.^ 

Having  shown  by  the  best  statistics  available  that  the  general 
phenomena  of  the  numerical  distribution  of  species  over  small 
or  large  areas  correspond  in  their  main  features  for  such 
diverse  groups  of  organisms  as  plants,  insects,  and  birds,  it 
is  quite  needless  —  even  if  it  were  possible  —  to  attempt  a 
similar  enumeration  for  other  groups.  In  reality,  with  the 
one  exception  of  land-shells,  the  materials  do  not  exist  for 
any  other  organisms.  Even  the  mammalia  and  reptiles  have 
never  been  systematically  collected  in  tropical  countries,  as 
hirds  and  insects  have  been  collected,  and  what  materials  do 
exist  are  more  difficult  to  obtain.  But  to  give  the  general 
reader  some  notion  of  the  extent  of  the  whole  world  of  life 
as  now  studied  by  biologists,  I  will  give  a  tabular  statement 
of  the  numbers  supposed  to  be  actually  described,  from  the 
estimate  made  by  Mr.  Shipley  above  referred  to  in  the  case 
of  insects. 

As  regards  these  figures,  I  am  informed  by  Mr.  R. 
Lydekker  that  he  considers  the  Mammalia  to  be  much  exag- 
gerated by  writers  who  reckon  slight  local  forms  or  varieties 
as  distinct  species.  Thus  8  species  have  been  made  of  the 
common  brown  bear,  and  16  species  of  various  local  forms 
of  mouse-deer  (Tragulus).  On  the  other  hand,  although  the 
number  of  insects  here  given  seems  enonnous,  Mr.  D.  Sharp, 
a  very  experienced  entomologist,  thinks  that  the  number  ac- 
tually existing  is  five  times  as  great  —  that  is,  more  than  two 
million  distinct  species ! 

1  Eor  a  full  explanation  of  the  six  great  Zoological  Regions,  here  enu- 
merated, the  reader  is  referred  to  my  Geographical  Distribution  of  Animals, 
vol.  i.  chap.  iv. ;  or  for  a  more  popular  account  of  them  to  my  Island  Life, 
chap.  ill. 


THE  DISTRIBUTION  OF  ANIMALS 


99 


An  Estimate  of  the  Described  Species  of  Living  Animals. 
By  A.  E.  Shipley,  F.R.S.   (B.  Essii.  Address,  1909). 


Class. 

Estimated  by 
Giinther,  18«1. 

A.  E.  Shiplev, 
1909. 

Remarks. 

Mammalia     

2,300 

11,000 

3,400 

11,000 

33,000 

120 

7,500 

8,070 

1,300 

220,150 

1,840 
6,070 
2,200 
400 
3,300 

9,955 

13,835 

7,180 

14,996 

62,000 

222 

13,953 

25,870 

8,725 

445,978 

15,097 
8,716 
5,008 
2,965 
6,000 

Too   hi»li ! 

Birds    

(R.    Lydekker). 

18,939 
(R.   B.  Sharpe). 

Reptiles,    Batrachia 

Fishes    

MoUusca    

Brvozoa,     

Crustacea    

Soiders.    etc 

MvriaDods     

Insects     

Too  low! 

Echinoderms     

(D.Sharp). 

Coelenterata           

. 

Snono-es   

Protozoa    

790,533 

CHAPTER  VI 

THE    I^UMEEICAL    DISTEIBUTION    OF    SPECIES    IN    RELATION"  » 

TO   EVOLUTION 

The  rather  lengthy  account  I  have  given  of  the  numerical 
distribution  of  species  over  both  small  and  large  areas,  and 
in  special  relation  to  latitude  and  to  climate,  has  a  very  def- 
inite object.  In  the  first  place,  this  distribution  constitutes 
the  primary  and  fundamental  fact  in  the  relation  of  species 
to  the  whole  environment  —  it  is,  in  fact,  the  broadest  and 
most  simple  expression  of  that  relation,  and  is  thus  a  proper 
subject  of  inquiry  in  any  general  view  of  the  world  of  life. 
Yet  it  has  been  strangely  neglected  both  by  botanical  and 
zoological  writers;  and  the  largest  and  oldest  collections  of 
plants  and  animals  in  all  countries  have  been  so  dealt  with  as 
to  afford  material  for  almost  every  form  of  biological  research 
except  this  one. 

The  mere  enumeration  of  the  numbers  of  species^  named  or 
unnamed,  with  the  localities  of  each  specimen,  in  the  great 
national  collections  of  the  world,  would  have  afforded  all  the 
materials  for  such  comparisons  as  I  have  here  endeavoured  to 
make.  And  if  the  facts  were  recorded  in  card-catalogues, 
instead  of  in  the  usual  forms,  there  would  be  such  a  demand 
for  sets  of  these  cards  applying  to  special  groups  and  definite 
geographical  areas,  by  most  students  or  collectors,  that  the  cost 
of  such  catalogues  would  be  more  than  repaid. 

This  numerical  relation  of  the  various  groups  of  organisms 
in  different  areas  or  geographical  divisions  of  the  earth  has 
the  further  advantage  of  being  interesting  and  intelligible  to 
the  general  reader,  as  it  involves  the  use  of  hardly  any  tech- 
nical terms,   and  is   therefore   especially   suitable  for   a   work 

100 


DISTKIBUTION  AND  EVOLUTION  101 

such  as  the  present.  We  will  now  proceed  to  a  brief  considera- 
tion of  the  nature  and  meaning  of  the  facts  set  forth  in  the 
preceding  chapters. 

The  evidence,  collected  with  extreme  care  for  many  years 
by  Mr.  Woodruffe-Peacock  (as  explained  in  Chapter  11.)?  has 
shown  us  how  curiously  the  number  of  species  differs  even 
on  the  smallest  adjacent  areas.  In  the  same  field,  even  when 
apparently  alike  everywhere  in  soil,  in  aspect,  and  in  contour 
of  surface,  every  plot  of  16  feet  square  has  its  individuality. 
It  will  differ  from  each  of  the  eight  adjacent  plots  either  in 
tlie  number  of  the  species  it  contains,  or  in  the  species  them- 
selves, or  in  the  proportions  of  the  individuals  of  the  various 
species.  They  are  thus  seen  to  be  affected  by  very  small 
differences,  such  as  moisture,  or  aridity;  more  or  less 
shade  from  hedges,  trees,  or  woods;  shelter  from  or  ex^^osure 
to  winds;  by  the  vicinity  of  pits  or  quarries,  woods,  ponds, 
or  streams. 

Now  this  one  fact  of  response  to  the  minutest  change  of 
conditions  in  the  arrangement  of  a  few^  species  over  almost 
identical  adjacent  areas  is  as  much  a  case  of  adaptation  to 
the  environment  through  the  mutual  interaction  of  the  various 
species  —  a  struggle  for  existence  on  the  very  smallest  scale 
' —  as  any  of  those  larger  and  more  complex  cases  which  Dar- 
win first  made  known  to  us. 

Coming  now  to  the  fields  themselves  of  various  shapes  and 
dimensions,  and  each  limited  by  definite  boundaries  of  hedge 
and  ditch,  bank  or  wall,  spinneys,  plantation  or  woods,  we 
have,  in  our  country  especially,  a  series  of  unit-areas  which 
may  be  said  to  form  the  first  step  in  the  study  of  botanical 
geography,  and  which  leads  us  on  through  successively  larger 
areas  to  regions  and  continents. 

In  regard  to  these  fields,  the  writer  above  quoted  not  only 
states  their  precise  differences  in  the  numbers  of  their  species 
and  the  presence  of  certain  species  and  absence  of  others  which 
give  to  each  its  individuality,  but  lie  is  able  in  many  cases 
to   define   the   causes   of  that   individiialitv.     Besides   the    or- 


102  THE  WORLD  OF  LIFE 

dinarj  variations  of  soil,  we  have  to  take  account  of  the  effects 
of  diversity  of  treatment  as  meadows,  pasture,  or  fallow  land, 
each  resulting  in  a  characteristic  grouping  of  species  easily 
recognisable  over  wide  areas.  In  pasture  land  each  kind 
of  domestic  animal  leads  to  the  presence  or  absence  of  certain 
species,  while  in  the  vicinity  of  farms  or  villages,  the  presence 
of  geese,  pigs,  or  poultry  has  a  distinctive  influence. 

What  a  new  light  these  researches  throw  upon  the  develop- 
ment of  the  vegetation  of  each  country  during  past  ages !  We 
see  how  the  indigenous  vegetation  of  oceanic  islands,  in  the 
total  absence  of  mammalia,  must  have  gradually  eliminated 
some  of  the  chance  immigrants  by  which  they  were  first 
stocked,  and  favoured  others  often  of  later  date,  and  how,  in 
the  com^^etition  with  each  other,  those  species  which  were  most 
easily  modified  into  a  shrubby  or  arboreal  type  would  have  the 
advantage.  Thus  may  we  explain  the  composites,  lobelias, 
violets,  and  plantains  of  the  Sandwich  Islands  being  mostly 
shrubs  or  even  trees  of  considerable  size,  and  so  abundant  in 
species  as  to  form  a  characteristic  feature  of  the  vegetation. 
Numerous  Caryophyllacese,  Primulacese,  and  a  Geranium  are 
also  shrubs  or  small  trees.  In  the  Azores  a  Campanula  and 
a  Sempervivum  are  shrubs. 

Again,  the  knowledge  we  have  recently  gained  of  the  won- 
derfully rich  mammalian  fauna  of  temperate  Xorth  America 
in  middle  and  late  Tertiarv  times  —  camels,  ancestral  horses 
and  cattle,  mastodons,  and  many  others,  which  disappeared 
at  the  on-coming  of  the  glacial  epoch  —  affords  us  a  very  im- 
portant clue  to  the  development  of  its  special  vegetation. 
Every  change  of  animal  life  that  so  often  occurred  in  all  the 
continents  —  the  union  and  separation  of  the  sub-arctic  lands 
at  various  epochs,  the  temporary  separation  of  Xorth  and  South 
America  in  late  Tertiarv  times,  and  that  of  Africa  from 
Europe  and  Asia  during  the  Early  and  Middle  Tertiary  — 
must  all  have  profoundly  affected  the  special  developments 
of  the  vegetation,  as  well  as  of  the  animal  life,  in  the  respec- 
tive areas. 


DISTKIEUTION  AND  EVOLUTION  103 

No  less  indicative  of  delicate  response  to  variation  of  tem- 
perature, and  therefore  of  close  adaptation  to  the  whole  modi- 
fied environment,  is  the  continuous  increase  in  the  number 
of  species  with  every  important  change  of  latitude.  Although 
this  increase  is  but  slight  for  moderate  changes,  and  is  there- 
fore liable  to  be  masked  by  other  favourable  or  adverse  con- 
ditions of  the  environment,  it  yet  makes  itself  visible  in  every 
continent ;  and  in  the  comparison  between  the  north  or  mid- 
temperate  and  the  tropical  zones  is  so  pronounced  that  in  fairly 
comparable  areas  the  tropical  species  are  often  (and  probably 
on  the  average)  double  those  of  the  temperate  zones.  This 
seems  to  be  the  case  among  the  higher  animals,  as  well  as 
among  all  the  vascular  plants. 

Now  all  this  is  indicative  of  long  and  minute  adjustment 
to  the  special  inorganic  as  well  as  the  organic  conditions ;  and 
the  reason  why  the  tropics  as  a  whole  far  surpass  the  temper- 
ate zones  in  the  number  of  their  specific  forms,  is,  not  the 
greater  amount  of  heat  alone,  but  rather  the  much  greater 
uniformity  of  climatical  conditions  generally,  during  long 
periods  —  perhaps  during  the  whole  range  of  geological  time. 
Whatever  changes  have  occurred  through  astronomical  causes, 
such  as  greater  excentricity  of  the  earth's  orbit,  must  neces- 
sarily have  produced  extremes  of  climate  towards  the  poles, 
while  the  equatorial  regions  would  remain  almost  unaffected, 
except  by  a  slight  and  very  slow  rise  or  fall  of  the  average 
temperature,  which  we  know  to  be  of  little  importance  to  vege- 
tation so  long  as  other  conditions  remain  tolerably  uniform 
and  favourable. 

It  is  this  long-continued  uniformity  of  favourable  condi- 
tions within  the  tropics,  or  more  properly  within  the  gi'eat 
equatorial  belt  about  2000  miles  in  width,  that  has  permitted 
and  greatly  favoured  ever-increasing  delicacy  of  adjustments 
of  the  various  species  to  their  whole  environment.  Thus  has 
arisen  that  multiplicity  of  species  intermingled  in  the  same 
areas,  none  being  able,  as  in  the  temperate  zone,  to  secure  such 
.a  superior  position  as  to  monoj)olise  large  areas  to  the  exclu- 


104  THE  WOELD  OF  LIFE 

sion  of  others.  Hence  also  it  has  come  about  that  the  equa- 
torial species  seem  to  be  better  defined  —  more  sharj^ly  dis- 
tin2;nished  from  each  other  —  than  manv  of  those  of  the  tem- 
perate  and  northern  zones.  They  are  what  Dr.  Beccari  terms 
first-grade  species,  as  in  the  case  of  Borneo,  an  island  which 
forms  part  of  what  has  quite  recently  been  an  equatorial  con- 
tinental mass.  It  is  interesting  to  note  that  Mr.  Th.  D.  A. 
Cockerell  has  arrived  at  a  similar  conclusion  from  his  study 
of  the  rich  fossil  flora  of  Florissant,  Colorado,  of  middle  or 
late  Tertiary  age,  which  shows  signs  of  a  much  milder  climate 
than  now  prevails  there.  Many  of  these  plants  are  of  genera 
now  extinct  or  only  found  in  more  southern  lands,  and  this  ex- 
tinction is  traceable  to  the  great  changes,  inorganic  and  or- 
ganic, that  have  since  occurred  in  Xorth  America.  He  says 
(in  a  private  letter)  : 

"  There  was  first  the  invasion  of  Old  World  species  via  Behring's 
Straits;  then  an  incursion  of  S.  American  forms  via  Panama;  and 
then  the  glacial  period  at  the  end,  crowding  and  destroying  much 
of  the  flora  and  fauna.  Since  the  glacial  period  in  X.  America, 
there  has  been  room  for  expansion,  and  hence  the  very  numerous 
and  closely  allied  species  of  Aster,  Solidago,  Senecio,  and  other 
jolants,  as  well  as  allied  species  of  butterflies  of  the  genera  Arg}^nnis, 
Colias,  etc.  These  are,  most  of  them,  not  at  all  on  the  same  footing 
as  the  tropical  species.  ...  I  think  tropical  species  are  better 
defined  than  those  of  the  temperate  region.'' 

It  is  a  rather  curious  coincidence  that  if  we  take  the  mean 
area  of  the  twelve  English  counties  for  which  I  have  been 
able  to  give  the  figures,  in  geographical  instead  of  English 
miles,  the  number  of  square  miles  will  almost  exactly  equal 
the  average  number  of  their  species  of  flowering  plants.  Be- 
low this  area,  in  the  mid-temperate  zone,  the  proportion  of 
species  decreases,  and  above  it  increases,  in  both  slowly  at 
first  and  with  many  fluctuations,  but  afterAvards  very  rapidly, 
more  especially  for  the  larger  areas,  so  that  it  requires  on  a 
rough  average  about  a  two  hundred-fold  increase  of  area  to 
double  the  number  of  species,   and   about   a   thousand-fold  to 


DISTRIBUTION  A^B  EVOLUTION  105 

qiuntuple  it.  But  in  all  such  comparisons  we  require  a  large 
number  of  fairly  comparable  cases  to  give  a  trustworthy 
average,  and  the  materials  for  this  do  not  seem  to  exist.  Yet 
there  is  a  striking  general  agreement  between  the  numbers 
of  the  species  in  the  various  kingdoms,  states,  or  colonies  of 
Europe,  North  America,  and  Australia,  requiring  only  slight 
allowances  for  greater  area,  better  climate,  or  geological  history 
to  bring  them  into  line  with  one  another  to  a  really  remarkable 
degree. 

It  appears,  then,  that,  whether  we  take  small  areas  roughly 
approximating  100  square  miles,  or  much  larger  areas  of  from 
100,000  to  200,000  square  miles,  there  is,  over  the  whole  world, 
an  unexpected  amount  of  agreement  in  the  numbers  of  the 
flowering  plants,  but  always  showing  a  moderate  increase  from 
the  colder  to  the  w^armer  parts  of  the  earth. 

Differences  of  Temperate  and  Tropical  Vegetation 

One  of  the  chief  differences  between  the  floras  of  the  colder 
and  of  the  warmer  parts  of  the  earth  (already  referred  to)  is 
the  greater  prevalence  in  the  former  of  gregarious  plants.  To- 
wards the  northern  limit  of  vegetation  we  find  continuous 
forests  of  pines  or  firs,  the  same  species  often  extending  for 
hundreds  or  even  thousands  of  miles ;  while  woods  of  birches 
extend  even  farther  north  almost  up  to  the  limits  of  perpetual 
snow,  and  in  this  case  a  single  species  —  our  common  birch  — • 
extends  entirely  across  northern  Europe  and  Asia,  with  allied 
species  in  North  America.  Earther  south,  forests  of  beeches, 
oaks,  chestnuts,  etc.,  are  common,  but  seldom  covering  such 
large  areas,  being  dependent  on  conditions  of  soil  as  well  as 
of  climate;  while  in  the  warmer  parts  of  the  temperate  zone 
the  forests  are  often  made  up  of  a  gTeat  variety  of  trees, 
though  never  so  completely  intermingled  as  in  the  typical  areas 
of  the  tropics. 

Another,  and  perhaps  more  important  character  of  the 
tropical  flora,  is  the  large  number  of  distinct  types  of  vegeta- 
tion which  are   almost  or  quite  peculiar  to  ihe   warmest   and 


lOG  THE  WORLD  OF  LIFE 

most  equable  regions  of  the  earth.  This  is  indicated  by  the 
fact  that  about  one-fourth  of  the  natural  orders  of  plants  are 
either  exclusively  tropical  or  very  nearly  so,  and  that  they 
comprise  such  remarkable  forms  as  the  epiphytic  Orchids,  the 
Bromelias,  the  Palms,  the  Pitcher-plants,  Bananas,  Bread- 
fruits, the  Coffea  and  Cinchona  trees,  and  hundreds  of  others 
almost  unknown  except  to  botanists. 

But  the  most  striking  feature  of  all  is  the  wonderful  adapta- 
tions by  which  every  w^ell-marked  place  or  station  is  occupied 
by  peculiar  groups  of  plants.  The  epiphytes  above  referred  to 
• —  plants  which  live  upon  trees,  upon  the  trunks  or  branches, 
and  especially  in  the  forks,  where  they  can  root  and  establish 
themselves,  not  as  parasites  by  sending  their  roots  into  the 
living  tissues  of  the  tree,  but  solely  getting  nourishment  from 
the  rain-water  that  trickles  down  the  bark  or  the  small  quan- 
tity of  decaying  leaves  or  moss  that  collects  there  —  such 
plants  belong  to  many  natural  orders  and  are  very  numerous. 
Then  there  are  the  climbers,  far  more  abundant  than  in  any 
temperate  forests,  which  either  root  in  the  ground  and  then, 
by  various  means,  climb  up  to  the  summits  of  the  loftiest 
trees,  or  which  begin  life  by  rooting  in  a  lofty  fork  of  a  gi-eat 
tree,  and  then  send  down  roots  to  the  ground  and  branches 
into  the  air,  sometimes  remaining  as  a  small  bush  or  tree,  at 
others  growing  so  rapidly  above,  and  clinging  around  the  sup- 
porting tree  so  closely  with  its  roots,  as  finally  to  kill  its  foster- 
parent,  when  its  clinging  roots  unite  and  grow  into  a  trunk, 
with  hardly  anything  to  show  that  one  tree  has  replaced  an- 
other. Then  again  there  are  numerous  small  trees  of  from  20 
to  30  feet  high,  which  live  entirely  in  the  shade  beneath  the 
great  forest  trees.  Many  of  these  have  bright-coloured  or  con- 
spicuous flowers  growing  directly  out  of  the  trunk,  while  there 
are  none  at  all  among  the  crown  of  leaves  at  the  top.  This  ap- 
pears to  be  an  adaptation  to  bring  the  flowers  within  sight  of 
the  butterflies,  bees,  and  other  insects  which  fly  near  the 
ground,  and  thus  secure  for  them  the  advantages  of  being 
cross-fertilised.     Then  again  there  are  many  delicate  creeping 


DISTRIBUTION  AND  EVOLUTION  107 

plants,  especially  mosses  and  hepaticse,  that  cover  the  whole 
surfaces  of  the  leaves  of  forest  trees  with  an  exquisite  tracery, 
thus  obtaining  the  perpetual  moisture  they  require  from  con- 
densation on  the  cool  surfaces  of  the  leaves. 

in  great  river  valleys,  where  by  the  annual  rising  of  the 
stream  miles  of  alluvial  plains  are  regularly  under  water  for 
several  months,  both  trees  and  shrubs  have  become  adapted  to 
these  strange  conditions,  and  the  greater  part,  if  not  all,  the 
species  are  quite  distinct  from  those  which  grow  on  the  un- 
flooded  land. 

All  these,  and  many  other  characteristic  features  of  tropical 
vegetation,  can  be  explained  by  the  general  constancy  of  the 
inorganic  conditions,  especially  the  climatic  ones,  which  have 
undoubtedly  prevailed  there  during  whole  geological  periods, 
subject  only  to  those  very  slow  changes  due  to  elevation,  de- 
pression, and  denudation  of  the  land  itself.  These  latter  have 
been  so  extremely  gradual  as  to  act  as  a  gentle  stimulus  to  the 
various  agencies  continually  bringing  about  modification  of 
specific  form? ;  and  as  the  climatal  conditions  throughout  all 
these  changes  have  continued  to  be  highly  favourable  to  the 
support  of  vegetation  and  of  animal  life,  there  has  been  a  con- 
stant tendency  to  produce  and  maintain  an  almost  exact 
equilibrium  between  the  various  species  in  the  same  area. 
None  being  better  adapted  to  the  environment  than  a  great 
many  others,  none  are  able  to  monopolise  large  areas  to  the 
exclusion  of  others,  as  is  the  case  in  the  more  changeable  tem- 
perate or  cold  regions.  Whether  we  consider  the  differences 
between  day  and  night  temperatures,  the  variations  of  tem- 
perature from  month  to  month  or  from  year  to  year,  or  those 
extreme  variations  which  we  experience  once  perhaps  in  a  gen- 
eration or  in  a  century,  such  as  excessively  cold  winters,  ex- 
cessive droughts  or  excessive  rains  in  summer,  or  long  periods 
of  dry  and  cold  winds  —  all  alike  are  unkno\\Ti  in  the  equa- 
torial regions,  save  in  a  few^  limited  and  quite  exceptional  areas. 
In  these  more  favoured  portions  of  our  earth  there  prevails 
such  a  general  approach  to  uniformity  of  conditions  (without 


108  THE  WOELD  OF  LIFE 

ever  reaching  absolute  uniformity)  as  seems  best  adapted  to 
bring  about  the  greatest  productivity,  together  with  extreme 
diversity  in  every  department  of  the  great  world  of  life. 

The  large  amount  of  diversity  of  species  we  have  seen  to  oc- 
cur in  single  fields  long  subject  to  almost  identical  conditions 
in  our  own  country,  wdth  the  additional  fact  that  no  plot  of  a 
fev7  square  yards  has  exactly  the  same  grouping  of  species  and 
individuals  as  any  of  the  other  plots,  yet  each  plot  produces 
very  nearly  the  same  number  of  species,  will  enable  us  in  some 
degree  to  appreciate  the  conditions  of  the  tropics.  There  we 
see  enormous  areas  subject  to  almost  identical  conditions  of 
soil,  climate,  and  rainfall,  yet  in  every  part  of  it  exhibiting, 
amid  a  general  -uniformity  of  type,  a  wonderful  diversity  in 
the  shapes  and  structures  of  the  forms  of  life,  and  a  no  less 
w^onderful  balance  and  adaptation  of  each  to  all.  How  this 
result  has  been  actually  brought  about  in  the  course  of  evolu- 
tion through  the  ages  we  shall  better  understand  after  a  brief 
exposition  of  the  factors  wdiich  have  been  the  immediate  causes 
of  the  two  great  phenomena,  continuous  evolution,  with  con- 
tinuous adaptation. 


CHAPTEE  VII 

HEREDITY,    VARIATION,    INCREASE 

In  the  preceding  chapters  I  have  shown  how,  from  a  con- 
sideration of  the  simple  facts  of  the  numerical  distribution  of 
species  over  the  earth,  together  with  the  varying  numbers  of 
the  individuals  in  each  species  and  the  area  occupied  by  them, 
we  are  led  to  the  conclusion  that  there  is  an  ever-present  strug- 
gle for  existence  between  species  and  species,  resulting  in  a 
continual  readjustment  to  the  environment.  In  this  view 
there  is  no  question  of  any  change  of  species,  but  merely  of 
their  redistribution;  we  perceive  that  during  the  process  very 
rare  or  local  species  may,  and  certainly  do,  die  out,  but  we 
have  obtained  no  clue  to  the  method  by  which  new  species  arise 
to  replace  them. 

This  was  the  state  of  opinion  among  the  most  advanced 
writers  before  Darwin,  and  it  is  very  clearly  expressed  in  the 
admirable  42nd  chapter  of  Sir  Charles  Lyell's  Principles  of 
Geology  (11th  edition,  18 68,  but  w^hich  first  appeared  in  the 
9th  edition,  1853,  pp.  689-701)  many  years  before  the  idea 
of  the  transmutation  of  species  had  been  seriously  entertained 
by  men  of  science.  This  chapter  may  still  be  read  with  in- 
terest even  by  the  evolutionist  of  to-daj^  The  reader  will  then 
be  better  able  to  appreciate  the  enormous  advance  made  by 
Darwin  by  his  conception  of  "  natural  selection,"  dependent 
on  the  three  fundamental  factors  —  heredity,  variation,  and 
enormous  powers  of  increase  —  all  well  known  to  naturalists, 
but  whose  combined  eifect  had  been  hitherto  unperceived  and 
neglected.  The  two  first  of  these  factors  we  will  now  pro- 
ceed to  discuss  and  elucidate. 

Perhaps  the  most  universal  fact  —  sometimes  termed  ^'  law  " 
—  of  the  organic  world  is,  that  like  produces  like  —  that  off- 

109 


110  THE  WORLD  OF  LIFE 

spring  are  like  their  parents.  This  is  so  common,  so  well 
known  to  everybody,  so  absolutely  universal  in  ordinary  ex- 
perience, that  we  are  only  surprised  when  there  seems  to  be 
any  exception  to  it.  In  its  widest  sense  as  applied  to  species 
there  are  no  exceptions.  Not  only  does  the  acorn  always  pro- 
duce an  oak,  the  cat  a  kitten,  which  grows  into  a  cat,  the  sheep 
a  lamb,  and  so  throughout  all  nature,  but  each  different  well- 
marked  race  also  produces  its  like.  We  recognise  Chinese  and 
Negroes  as  being  men  of  the  same  species  as  ourselves  but  of 
different  varieties  or  races,  yet  these  varieties  always  produce 
their  like,  and  no  case  has  ever  occurred  of  either  race  pro- 
ducing offspring  in  every  respect  like  one  of  the  other  races, 
any  more  than  there  are  cases  of  cart  horses  producing  racers 
or  spaniels  producing  greyhounds. 

Some  people  still  think  that  mental  qualities  are  not  in- 
herited, because  it  so  often  happens  that  men  of  genius  have 
quite  undistingaiished  parents,  and  that  the  children  of  men 
of  great  ability  do  not  as  a  rule  equal  their  fathers.  But  al- 
though such  cases  are  frequent  and  attract  attention  because 
such  apparent  non-inheritance  is  unexpected  and  seems  un- 
reasonable, yet  when  large  numbers  of  families  are  carefully 
examined  there  is  found  to  be  the  same  amount  of  mental  as 
of  physical  inheritance.  This  was  proved  by  Sir  Francis 
Galton  in  his  work  on  Hereditary  Genius,  in  which,  by  tracing 
the  families  of  large  numbers  of  public  men  of  high  position 
and  some  kind  of  exceptional  talent  or  genius  which  was  gen- 
erally recognised,  it  was  found  that  in  their  ancestral  line 
there  was  always  found  some  amount  of  distinction,  though 
not  always  of  the  same  kind  or  degree;  and  that  if  they  left 
descendants  for  two  or  three  generations,  they,  too,  usually 
comprised  some  individuals  of  more  than  average  ability. 

To  avoid  any  misconception  on  this  point,  it  may  be  as  well 
here  to  state  brieflv  the  numerical  law  of  inheritance,  which 
Galton  arrived  at  by  careful  experiments  in  the  breeding  of 
plants  and  animals,  and  which  is  now  generally  accepted  as 
affording  a  very  close  representation  of  the  facts  of  inherit- 


HEREDITY,  VARIATION  111 

V 

ance  under  normal  conditions.  It  is  that  the  offspring  of  any 
two  parents  derive,  on  the  average,  one-half  of  their  character- 
istics from  tliose  parents,  one-fourth  from  their  four  grand- 
parents, one-eighth  from  their  eight  great-grandparents,  and 
so  on  to  remote  ancestry,  the  total  result  being  that  one-half 
of  each  individual's  peculiarities  is  derived  from  its  parents, 
while  the  other  half  comes  from  its  whole  previous  ancestry. 
Hence  arises  the  Avell-known  fact  that  certain  peculiarities  of 
body  or  of  character  are  apt  to  reappear  in  families  during 
several  centuries. 

Xow  this  simple  law  explains  almost  all  the  facts  including 
the  apparent  failures  of  inheritance  —  all  its  irregularities  in  in- 
dividual cases,  together  with  its  constancy  and  regularity  when 
larse  numbers  are  examined.  It  shows  us  whv,  when  families 
for  several  generations  have  been  noted  for  beauty,  for  stature, 
for  strength,  or  for  talent,  these  characters  will  almost  cer- 
tainly be  found  developed  in  most  of  their  children,  who  from 
three  or  four  generations  of  ancestors  have  a  good  chance  of  de- 
riving seven-eighths  or  fifteen-sixteenths  of  their  entire  or- 
ganisations. If,  on  the  other  hand,  the  beauty  or  talent  of 
jjarents  were  exceptional  in  their  respective  families,  then 
iheir  children,  having  a  number  of  commonplace  or  inferior 
ancestors,  w^ould  often  be  far  inferior  to  their  parents  in  the 
particulars  in  which  the  parents  excelled,  and  in  their  case 
heredity  would  seem  to  have  failed. 

Erom  this  consideration  there  is  deduced  another  general 
law,  very  easy  to  remember  and  of  great  use  in  explaining  ap- 
parent deviations  or  incongruities.  This  is  called  the  '^  law"  of 
recession  towards  mediocrity."  It  means  that,  whenever  par- 
ents deviate  considerably  from  the  average  of  the  population 
of  which  they  form  a  part,  their  offspring  will  tend  to  return 
towards  the  average.  Eor  example,  if  both  parents  are  de- 
cidedly below  or  above  the  average  in  height,  in  beauty  of 
form,  in  any  special  faculty,  as  music,  drawing,  etc.,  their  chil- 
dren will  usuallv  ffo  back  towards  the  averaii'e,  thou2:li  still  re- 
taining  some  of  the  parental  excess  or  defect.      It  is  owing  to 


112  THE  WORLD  OF  LIFE 

tliis  law  that  very  extreme  developments,  whether  of  body  or 
of  mind  —  gigantic  stature  or  supreme  genius  —  are  rarely 
transmitted  to  the  next  generation.  But  if  this  special  su- 
periority has  already  persisted  in  the  family  for  several  gen- 
erations, and  both  parents  belong  to  this  same  superior  stock, 
then  the  reversion  towards  mediocrity  is  less  marked,  and  the 
special  quality  will  almost  certainly  be  transmitted,  sometimes 
even  in  still  larger  degree,  to  some  members  of  the  family. 

It  is  by  acting  on  this  principle  that  breeders  of  animals  or 
j^lants  for  special  purposes  are  able  to  improve  the  race.  In 
each  generation  they  choose  the  most  perfect  individuals,  from 
their  point  of  view^,  to  be  the  parents  of  the  next  generation,  re- 
jecting or  destroying  all  the  inferior  ones.  It  is  in  this  way 
that  our  race-horses,  our  best  milking  cows,  our  heavy-woolled 
sheep,  our  quickly  fattening  pigs,  our  luscious  pears  and 
peaches,  and  hundreds  of  others,  have  been  produced.  Just 
in  proportion  as  we  have  bred  only  from  the  best  for  a  long 
series  of  generations  does  the  transmission  of  these  qualities 
become  more  certain  and  the  ''  recession  tow^ards  mediocrity  " 
appear  to  be  abolished.  But  it  is  not  really  abolished.  The 
average  to  w^hich  there  is  a  tendency  to  return  has  itself  been 
raised  by  careful  selection  of  the  best  for  many  generations, 
and  the  inferior  individuals  which  were  once  the  average  of 
the  race  are  now  so  far  removed  that  they  can  exert  only  a 
very  slight  influence  on  each  successive  generation.  Owing  to 
the  numerical  law  above  referred  to,  after  five  generations  of 
such  selective  breeding  it  is  about  100  to  1  against  the  inferior 
characters  of  the  original  average  stock  reappearing  in  the 
offspring,  while  if  the  operation  has  been  carried  on  for  ten 
generations  it  is  about  2000  to  1  against  such  inferior  types 
presenting  themselves.  It  is  for  this  reason  that  our  great 
Colonial  sheep  and  cattle  breeders  find  it  to  their  advantage 
to  give  even  thousands  of  pounds  for  pedigree  bulls  or  rams 
in  order  to  improve  their  stocks. 

It  is  by  what  is  substantially  the  same  process,  as  wt  shall 
see  farther  on,  that  nature  works  to  improve  her  stocks  in  the 


HEEEDITY,  VAEIATION  113 

great  world  of  life ;  and  has  been  thus  enabled  nut  only  to  keep 
all  in  complete  adaptation  to  an  ever-varying  environment,  but 
to  fill  up,  as  it  were,  every  element,  every  different  station, 
every  crack  and  crevice  in  the  earth's  surface  with  wonderful 
and  beautiful  creatures  which  it  is  the  privilege  and  delight 
of  the  naturalist  to  seek  out,  to  study,  and  to  mar\^el  at. 

The  Variation  of  Species,  its  Frequency  and  its  Amount 

Having  now  shown  something  of  the  nature  of  heredity,  its 
universality  and  its  limitations,  we  pass  on  to  a  rather  fuller 
discussion  of  the  nature  and  amount  of  those  limitations,  com- 
monly known  as  the  variability  of  species.  It  is  this  variability 
that  constitutes  the  most  important  of  the  factors  which  bring 
about  adaptation,  and  that  peculiar  change  or  modification  of 
living  things  which  we  term  distinct  species.  This  change  is 
often  very  small  in  amount,  but  it  always  extends  to  various 
parts  or  organs,  and  so  pervades  the  whole  structure  as  to 
modify  to  a  perceptible  extent  the  habits  and  mode  of  life,  the 
actions  and  motions,  so  that  we  come  to  recognise  each  species 
as  a  complete  entity  distinct  from  all  others. 

There  is  no  subject  of  such  vital  importance  to  an  adequate 
conception  of  evolution,  w^hich  is  yet  so  frequently  misappre- 
hended, as  variability.  Perhaps  owing  to  the  long-continued 
and  inveterate  belief  in  the  immutability  of  species,  the  earlier 
naturalists  came  to  look  upon  those  conspicuous  cases  of  varia- 
tion which  forced  themselves  upon  their  attention  as  something 
altogether  abnormal  and  of  no  importance  in  the  scheme  of 
nature.  Some  of  them  went  so  far  as  to  reject  them  altogether 
from  their  collections  as  interfering  with  the  well-marked  dis- 
tinctness of  species,  which  they  considered  to  be  a  fundamental 
and  certain  fact  of  nature.  Hence,  perhaps,  it  was  that  Dar- 
win himself,  finding  so  little  reference  to  variation  among  wild 
animals  or  plants  in  the  works  of  the  writers  of  his  time,  had 
no  adequate  conception  of  its  universality  or  of  its  large  general 
amount  whenever  extensive  series  of  individuals  were  com- 
pared.    He  therefore  always  guarded  himself  against  assuming 


114  THE  WORLD  OF  LIFE 

its  presence  whenever  required  bj  using  such  exj^ressions  in 
regard  to  the  power  of  natural  selection  as,  ''  If  thej  vary,  for 
unless  thej  do  so,  natural  selection  can  effect  nothing." 

This  was  the  more  strange  because  wherever  we  look  around 
us  we  find,  in  our  own  species,  in  our  own  race,  in  our  own 
special  section  of  that  race,  an  amount  of  variation  so  large 
and  so  universal  as  to  fully  satisfy  all  the  needs  of  the  evolu- 
tionist for  bringing  about  w^hatever  changes  in  form,  structure, 
habits  or  faculties  that  may  be  desired.  By  simply  observing 
the  people  we  daily  meet  in  the  street,  in  the  railway  carriage, 
at  all  public  assemblages,  among  rich  and  poor,  among  lowly- 
born  or  high-born  alike,  variability  stares  us  in  the  face.  We 
see,  for  instance,  not  rarely,  but  almost  daily  and  everywhere, 
short  and  tall  men  and  w^omen.  We  do  not  require  to  measure 
them  or  to  be  specially  good  judges  of  height  to  be  able  to 
observe  this  —  the  difference  is  not  one  of  fractions  of  an 
inch  only,  but  of  wdiole  inches,  and  even  of  several  inches. 
We  cannot  go  about  much  without  constantly  seeing  short 
men  who  are  about  5  feet  2  inches  high,  and  tall  men  who  are 
6  feet  2  inches  —  a  difference  of  a  w^hole  foot,  while  in  almost 
every  town  of  say  10,000  inhabitants,  still  greater  differences 
are  to  be  found. 

But  this  special  variation,  so  large  and  so  frequent  that  it 
cannot  be  overlooked,  is  only  one  out  of  many  which  we  may 
observe  daily  if  we  look  for  them.  Some  men  have  long  legs 
and  short  bodies,  others  the  reverse ;  some  are  long-armed,  some 
are  big-handed,  some  big-footed,  and  these  differences  are  found 
in  men  differing  little  or  nothing  in  height.  Again  we  have 
big-headed  and  small-headed  men,  long-headed  and  round- 
headed,  big-jawed,  big-eared,  big-eyed  men,  and  the  reverse; 
we  see  dark  and  light  complexions,  smooth  or  hairy  faces ; 
black,  or  brown,  or  red,  or  flaxen-haired  men;  slender  or  stout 
men,  broad  or  narrow-chested,  clumsy  or  graceful,  energetic 
and  active,  or  lazy  and  slow.  Characters,  too,  vary  just  as 
much.  Men  are  taciturn  or  talkative,  cool  or  passionate,  intel- 
ligent or  stupid,  poetical  or  prosy,  witty  or  obtuse.     And  all 


HEREDITY,  \^xUaAT10X  115 

these  characteristics,  whether  physical  or  mental,  are  combined 
together  iii  an  infinite  variety  of  ways,  as  if  each  of  them 
varied  independently  with  no  constant  or  even  usual  associa- 
tion with  any  of  the  others;  whence  arises  that  wonderful 
diversity  of  appearance,  attitudes,  expression,  ability,  intellect, 
emotion,  and  what  we  term  as  a  wdiole  character,  which  adds 
so  much  to  the  possibilities  and  enjoyments  of  social  life,  and 
gives  us  in  their  higher  developments  such  mountain  peaks  of 
human  nature  as  were  manifested  in  Socrates  and  Plato,  Homer 
and  Virgil,  Alexander  and  Phidias,  Buddha  and  Confucius  in 
the  older  world ;  in  Shakespeare  and  ^N^ewton,  Michael  Angelo, 
Faradav,  and  Darwin  in  more  recent  times. 

And  with  all  this  endless  variation  wherever  we  look  for  it, 
we  are  told  again  and  again  in  frequent  reiteration,  that  varia- 
tion is  minute,  is  even  infinitesimal,  and  only  occurs  at  long 
intervals  in  single  individuals,  and  that  it  is  quite  insufficient 
for  natural  selection  to  work  with  in  the  production  of  new 
species. 

This  blindness,  no  doubt,  arose  in  some  persons  from  the 
ingrained  idea  of  man's  special  creation,  at  all  events,  and  that 
it  was  almost  impious  to  suppose  that  these  variations  could 
have  had  anything  to  do  with  his  development  from  some 
lower  forms.  But  among  naturalists  the  idea  long  prevailed, 
as  it  does  still  to  some  extent,  that  in  a  state  of  nature  there 
is  little  variation.  Yet  here,  too,  they  might  have  found  a 
clue  in  the  fact,  so  often  quoted,  that  a  shepherd  knows  every 
individual  sheep  in  his  flock,  and  the  huntsman  every  dog  in 
his  well-matched  pack  of  hounds,  and  this  notwithstanding 
that  in  both  cases  these  animals  are  selected  breeds  in  which 
all  large  deviations  from  the  type  form  are  usually  rejected. 

Of  late  years,  however,  variations  occurring  in  a  state  of 
nature  have  been  carefullv  examined  and  measured,  and  it  is 
to  some  of  these  that  w^e  will  now  appeal  for  the  proof  of  ever- 
present  variation  of  the  character  and  amount  needed  for  the 
production  of  new  species  and  of  every  kind  of  adaptation  by 
means  of  natural  selection  or  the  survival  of  the  fittest.     Be- 


110 


THE  WOKLD  OF  LIFE 


fore  giving  examples  of  the  variation  of  the  higher  animals 
it  will  be  advisable  to  show  Avhat  is  meant  bv  the  "  law  of 
frequency "  of  variations  which  has  been  established  by  the 
measurement  of  several  thousands  of  men  in  various  countries 
of  Europe.  These  when  recorded  by  means  of  a  diagram  are 
found  to  form  a  very  regular  curve,  which  becomes  more  and 
more  regular  the  larger  are  the  numbers  measured.  The  im- 
portance of  this  is  that  when  we  have  only  small  numbers  of 
animals  to  deal  with,  and  we  find  great  irregularity  in  their 
diagrams,  we  are  sure  that  if  we  had  measurements  of  hun- 
dreds or  thousands  the  curves  would  be  equally  regular ;  and 
this  has  now  been  found  to  be  the  case. 

The  law  alluded  to  is  that  the  number  of  individuals  show- 
ing any  particular  amount  of  variation  is  in  inverse  proportion 
to  its  departure  from  the  mean  value  in  the  species.  It  is  very 
closely  represented  by  a  special  curve  called  by  mathematicians 
the  ''  curve  of  eiTor,"  but  for  our  purpose  may  be  termed  the 
curve  of  frequency. 

The  diagram  here  given  represents  this  curve  obtained  by^ 


mimm 


^i^V:::^::::::.::..:... 


Dwarfs.  Average    Men  Giant*. 

CURVE    OF    STATURE.  (BRITISH). 

Fig.  9.—  Diagi-am  of  Heiglit  of  2600  Men. 

measuring  the  heights   of   a   large  number  of  men   taken  at 
random. 

The  horizontal  scale  shows  the  heights  given  in  feet  and 
inches,  and  the  vertical  scale  the  numbers  measured  of  suc- 
cessive heights.      The  central  line  through  the  highest  point  of 


HEEEDITY,  ViVEIATIOE"  117 

the  curve  marks  the  average  of  the  whole  number  measured, 
there  being  in  this  case  (though  not  always)  very  nearly 
the  same  number  of  individuals  above  and  below  the  mean 
height. 

The  peculiarity  of  the  curve  is  that  it  rises  very  slowly  from 
the  height  marking  that  of  the  shortest  individual  measured  — 
here  a  fraction  above  4  feet  8  inches  —  then  more  and  more 
rapidly  for  about  one-third  of  the  height,  then  more  rapidly 
and  nearly  regularly  to  near  the  summit,  when  it  bends  in 
rather  abruptly  to  the  mean  height,  and  then  descends  in  a 
nearly  corresponding  curve  as  heights  are  above  the  average, 
till  it  ends  just  short  of  6  feet  8  inches. 

By  adding  together  the  numbers  on  both  sides  of  the  curve 
we  find  that  in  this  particular  group  of  2600  men  none  were 
quite  so  short  as  4  feet  8  inches  or  quite  so  tall  as  6  feet  8 
inches.  But  in  any  other  group  of  the  same  number  the  ex- 
tremes might  be  a  little  more  or  less,  perhaps  a  quarter  of 
an  inch  or  rarely  a  whole  inch.  We  should  have  to  measure 
a  million,  or  even  several  millions,  to  get  the  average  height 
and  the  proportionate  greatest  and  least  heights ;  and  even  then 
we  should  not  get  near  the  absolute  limits  of  our  race,  as  we 
know  that  at  long  intervals  giants  and  dwarfs  appear,  differing 
by  many  inches,  or  even  by  a  foot,  from  all  others  living  at 
the  time.  But,  omitting  these  rare  occurrences,  the  measure- 
ments of  a  few  thousand  among  a  fairly  mixed  population  will 
give  us  the  mean  height  of  the  whole,  very  nearh^;  as  well 
as  the  proportionate  numbers  of  those  of  particular  heights, 
as,  for  example,  at  5  feet  3  inches  or  6  feet  3  inches.  But 
even  the  mean  height  does  not  remain  the  same  if  the  mode 
of  life  changes.  It  is  certain  that  the  larger  proportion  now 
living  in  crowded  cities  than  there  were  a  century  ago  has 
considerably  dwarfed  our  population. 

We  will  now  give  an  example  of  variation  in  a  wild 
animal  in  order  to  show  that  man  and  the  animals  and  plants 
which  he  has  domesticated  or  cultivated  do  not  differ  in  this 
respect  from  those  existing  in  a  state  of  nature. 


118 


THE  WORLD  OF  LIFE 


The  diagram  here  given  is  formed  from  the  measurements 
of  six  separate  portions  of  twenty  male  specimens  of  the  Bob- 
o'-link  or  Rice-bird  (Dolichonyx  oryzivorus)^  very  common  in 
I^orth  America.  All  were  obtained  in  the  same  place  on  the 
same  day,  so  that  there  could  be  no  suspicion  of  their  being 


Inches 
6    i    2 


g    JO   ]]   22  23   24  25  26  27  28  J9  20  5 


1    2    3    4    5    6    7    3    9  lO  22  22  23  14  J3  16  27  28  29  20 

Rice-hird  ( Dolicho2iyX'Oryz2voras  .J  30  Males 


Fig.  10, —  Diagram  of  Variation. 


HEKEDITY,  VAlUATiOiV  119 

in  anv  way  selected  as  especially  variable.  It  is  a  little  larger 
than  our  yellow-hammer^  and  is  therefore  of  a  convenient 
size  to  be  shown  on  a  diagram  of  its  actual  dimensions,  thus 
giving  a  better  notion  of  the  amount  of  variation  of  the  several 
parts  than  if  reduced  to  a  smaller  scale. 

The  vertical  lines,  numbered  at  top  and  bottom,  1-20,  show 
the  measurements  of  the  tw^enty  specimens  of  this  bird,  and 
the  figures  at  the  sides,  0-5,  mark  the  inches.  The  specimens 
are  arranged  in  the  order  of  length  of  body,  shown  by  the 
upper  somewhat  irregularly  curved  line  of  dots.  This  is  seen 
to  vary  from  4%  inches  to  a  little  less  than  5  inches.  The 
next  lower  line  show^s  the  length  of  the  wing  of  each  specimen, 
and  we  at  once  see  the  want  of  correspondence  with  that  of 
the  body.  ^o.  5,  w^ith  a  quite  short  body,  has  the  longest 
wing  of  all;  while  No.  16,  with  a  long  body,  has  nearly  the 
shortest  wing.  The  third  line,  showdng  the  tail-lengths,  is 
equally  remarkable,  for  No.  6  shows  the  longest  tail  with  quite 
a  short  body,  while  No.  16,  with  one  of  the  shortest  tails,  has 
a  long  body;  so  that  Nos.  6  and  16,  measured  in  the  usual  way 
to  the  end  of  the  tail,  would  be  found  of  exactly  the  same  size, 
though  the  one  is  really  %  inch  shorter  than  the  other. 

The  next  three  lines  show  the  varying  lengths  of  the  tarsus 
(commonly  termed  the  leg),  the  middle  toe,  and  the  outer  toe, 
and  they  too  show  very  distinct  and  often  contrasted  divergences 
in  proportion  to  their  small  total  length.  Thus  Nos.  11  and  18 
have  nearly  the  shortest  legs  with  large  bodies.  The  middle 
toe  in  7  is  as  long  as  in  19  and  20,  while  the  outer  toe  is 
decidedly  longer  than  in  19,  and  in  12  decidedly  shorter  than 
in  2. 

It  is  particularly  important  to  note  here  that  this  remarkable 
amount  of  variation  occurs  in  only  tw^enty  birds  taken  at 
random.  But  the  species  is  one  of  the  most  populous  in  North 
America,  occurring  in  enormous  flocks  over  the  whole  conti- 
nent, from  54°  N.  lat.  in  summer,  and  migrating  as  far  south 
as  Paraguay  in  winter.  There  must,  therefore,  be  an  average 
population  of  (probably)  hundreds  of  millions,  giving  a  much 


120  THE  WORLD  OF  LIFE 

greater  range  of  variation,  and  an  ever-present  abundance  of 
variations  of  all  the  parts  and  organs  of  the  species. 

In  my  Darwinism  (chapter  iii.)  I  have  given  sixteen  dia- 
grams of  variation,  showing  that  it  ocenrs  to  an  approximately 
equal  extent  in  mammals  and  reptiles  as  well  as  in  birds,  and 
in  a  large  number  of  their  parts  and  external  organs;  while 
many  examples  of  variation  occur  among  the  lower  animals, 
especially  insects,  and  also  to  an  amazing  extent  among  plants. 
During  the  last  twenty  years  an  enormous  amount  of  work 
has  been  done  in  the  investigation  of  variation  in  all  its  phases 
and  complexities,  and  an  excellent  accoimt  of  these  has  been 
given  by  Dr.  H.  M.  Yernon  in  his  Variation  in  Animals  and 
Plants,  1903  (International  Scientific  Series),  to  which  my 
readers  are  referred  for  fuller  information,  but  a  few  of  his 
conclusions  may  be  here  given.     He  says : 

"  Every  organism  varies  in  respect  of  all  its  characters,  what- 
ever be  their  nature.  The  amount  of  this  variation  differs  greatly, 
but  it  is  always  present  in  a  greater  or  less  degree." 

And  again,  referring  to  a  diagram  showing  the  variations  of 
a  squirrel,  he  says: 

"  Variation  of  a  similar  nature  —  though  of  a  varying  degree  — 
is  present  in  all  organisms,  to  whatever  class  of  the  animal  or 
vegetable  kingdom  they  belong." 

Eef erring  to  the  diagram  of  human  stature  at  p.  116,  it  is 
found  that  about  half  the  whole  number  measured  vary  a  little 
more  than  2  inches  above  or  below  the  mean,  or  a  little  more 
than  3  per  cent  of  the  mean  height.  This  is  termed  the  per- 
centage of  mean  error,  and  Mr.  Vernon  gives  us  an  interesting 
table  of  the  same  percentage  for  different  parts  of  the  body 
derived  from  very  larg-e  numbers  of  measurements  of  different 
races  of  men.     It  is  as  follows :  — 


HEREDITY,  VARIATION 


121 


Per  cent. 

Nose  length   9.46 

"     breadth 7.57 

''     height     15.2 

Forehead    height    10.4 

Under-jaw    length 4.81 

Mouth  bretidtJi 5.18 


Per  cent. 

Head   length 2.44 

"       breadth 2.78 

Upper  arm  length G.50 

Fore   arm   length 3.85 

Upper    leg   length 5.00 

Lower             "          5.04 

Foot  length 5.92 


Here  we  see  that  the  different  parts  of  the  human  body  vary 
more,  proportionally,  than  does  its  whole  height ;  and  we  must 
always  remember  that  these  variations  are  all,  to  a  large  extent, 
independent  of  each  other,  just  as  we  saw  was  the  case  with 
those  parts  shown  in  the  bird  diagram. 

Again  Ave  must  lay  stress  upon  the  fact  that  every  part  of 
every  organism,  outside  or  inside,  important  or  insignificant, 
is  subject  to  a  similar  and  often  more  pronounced  amount  of 
variation,  as  numerous  examples  quoted  in  Mr.  Vernon's  book 
amply  prove.  So  that  we  are  fully  justified  in  accepting  as  a 
demonstrated  fact,  that  the  whole  structure  of  every  organism, 
in  every  stage  of  its  growth  or  development,  varies  in  its  dif- 
ferent individuals,  each  one  in  a  somewhat  different  manner, 
and  to  such  a  large  extent  as  to  afford  the  amplest  store  of 
material  for  modification  and  development  in  any  direction 
that  may  be  required. 

This  ever-present  and  all-pei"vading  variability  is  probably 
the  most  important  of  the  contributory  factors  of  evolution, 
and  must  never  for  a  single  moment  be  lost  sight  of. 

Powers  of  Increase  of  Plants  and  Animals 

Of  almost  equal  importance  with  ever-present  variation  is 
the  power  which  all  organisms  possess  of  reproducing  their 
kind  so  rapidly  as  to  be  able  to  take  possession  of  any  unoc- 
cupied spaces  around  them,  and  in  many  cases  to  expel  other 
kinds  by  the  vigour  of  their  growth. 

The  rapidity  of  increase  is  most  prominently  seen  among 
vegetables.  These  are  capable,  not  only  of  a  fivefold  nr  ten- 
fold  annual   increase,  as  am<^iii:-  many  of  the  higher  animals, 


122  THE  WORLD  OF  LIFE 

but  one  of  many  hundred  or  even  thousandfold  annually.  A 
full-grown  oak  or  beech  tree  is  often  laden  with  fruit  on  every 
branch,  which  must  often  reach  100,000,  and  sometimes  per- 
haps a  million  in  number,  each  acorn  or  nut  being  capable, 
under  favourable  conditions,  of  growing  into  a  tree  like  its 
parent.  Our  wild  cherries,  hawthorns,  and  many  other  trees, 
are  almost  equally  abundant  fruit-bearers,  but  in  all  these  cases 
it  is  only  rarely  (in  a  state  of  nature)  that  any  one  seed  grows 
to  a  fruit-bearing  size,  because,  all  having  a  superabundance 
of  reproductive  power,  an  equilibrium  has  been  reached  every- 
where, and  it  is  only  when  some  vacancy  occurs,  as  when  a 
tempest  uproots  or  destroys  a  number  of  trees,  or  some  diminu- 
tion of  grazing  animals  allows  more  seedlings  than  usual  to 
grow  up,  that  any  of  the  seeds  of  the  various  trees  around 
have  a  chance  of  sun'iving;  and  the  most  vigorous  of  these 
wall  fill  up  the  various  gaps  that  have  been  produced. 

But  it  is  among  the  herbaceous  plants  that  perhaps  even 
gi'eater  powers  of  increase  exist.  Where  our  common  fox-glove 
luxuriates  we  often  see  its  tall  spikes  densely  packed  with 
capsules,  each  crowded  with  hundreds  of  minute  seeds,  which 
are  scattered  by  the  wind  over  the  surrounding  fields,  but  only 
a  few  which  are  carried  to  especially  favourable  spots  serve 
to  keep  up  the  supply  of  plants.  Kerncr,  in  his  Xatural  His- 
tory of  Plants,  tells  us  that  a  crucifer,  Sisymhrium  Sophia, 
has  been  found  to  produce  on  an  average  730,000  seeds,  so  that 
if  vacant  spaces  of  suitable  land  existed  around  it,  one  plant 
might,  in  three  years  only,  cover  an  area  equal  to  2000  times 
that  of  the  land-surface  of  the  globe.  A  close  ally  of  this, 
Sisymhrium  Irio,  is  said  to  have  sprung  up  abundantly  among 
the  ruins  of  London  after  the  great  fire  of  1666.  Yet  it  is 
not  a  common  plant,  and  is  a  doubtful  native,  only  occurring 
occasionallv  in  En2^1ish  localities. 

Turning  to  the  animal  kingdom,  we  still  find  the  repro- 
ductive powers  always  large  and  often  enonnous.  The  slowest 
breeding  of  all  is  the  elephant,  which  is  supposed  to  rear  one 
young  one  every  10  years ;  but,  as  it  lives  to  more  than  100 


HEEEDITY,  VAEIATION  123 

years,  Darwin  calculates,  that  in  750  years  (a  few  mouients 
only  in  the  geological  history  of  the  earth)  each  pair  wuiikl, 
if  all  their  offspring  lived  and  bred,  produce  19  millions  of 
elephants. 

The  smaller  mammals  and  most  birds  increase  much  more 
rapidly,  as  many  of  them  produce  two  or  more  families  every 
year.  The  rabbit  is  one  of  the  most  rapid,  and  ^Ir.  Kearton 
calculates  that,  under  the  most  favourable  conditions,  a  single 
pair  might  in  4  or  5  years  increase  to  a  million.  Australia, 
being  favourable  in  climate,  vegetation,  and  absence  of  ene- 
mies, they  have  so  multiplied  as  to  become  a  nuisance  and 
almost  a  danger,  and  though  their  introduction  was  easy,  it 
has  so  far  been  found  impossible  to  get  rid  of  them. 

When  the  general  adaptation  of  an  animal  to  its  whole  con- 
ditions of  life  over  a  large  area  is  favourable,  an  enormous 
population  can  permanently  maintain  itself  in  the  face  of  what 
appear  to  be  dangerous  enemies.  Two  cases  illustrate  this,  and 
at  the  same  time  show  how  the  presence  of  civilised  man  leads 
to  their  rapid  extinction. 

In  the  eighteenth  century  the  bison  ranged  over  almost  the 
w^hole  of  temperate  Xorth  America,  being  abundant  in  Penn- 
sylvania and  Kentucky,  as  well  as  over  the  whole  of  the  central 
plains,  while  it  sometimes  extended  to  the  coast  of  the  Atlantic. 
Within  the  memor)^  of  living  persons  it  abounded  west  of  the 
Mississippi  in  countless  herds  many  miles  in  extent,  as  vividly 
described  by  Catlin  the  painter,  in  the  stories  of  Mayne  Reid, 
and  in  the  narratives  of  numerous  travellers  and  explorers. 

The  fact  that  such  a  large  and  rather  clumsy  animal  should 
under  natural  conditions  have  occupied  so  large  an  area  in 
such  vast  multitudes,  is  a  sure  proof  that  it  had  become  so 
perfectly  adapted  to  its  whole  environment  as  to  effectually 
protect  itself  against  the  numerous  enemies  that  inhabited  the 
same  area.  Those  powerful  members  of  the  cat  tribe,  the 
jaguar  and  the  puma,  would  have  been  quite  able  to  destroy 
the  bison  had  it  not  been  protected  by  its  social  instinct  and 
high  intelligence.      The  wolves  which  hunt  in  packs,  and  are 


124 


THE  WOraD  OF  LIFE 


equally  po^verful  and  ferocious  mth  those  of  Europe,  must 
also  have  been  most  dangerous  enemies;  but  the  bisons  always 
associated  in  numerous  herds,  and  were  so  well  guarded  by  the 
old  males,  that  they  apj^ear  to  have  suffered  little  from  these 
animals.     The   immense   shaggy   covering   to   the   head,   neck, 


Fig.  11. —  The  American  Bison  {Bos  Americanus) . 

and  breast  of  the  male  buffaloes,  together  with  their  short, 
powerful  horns,  were  an  almost  perfect  protection ;  and  we 
must  consider  these  animals  to  have  constituted  one  of  the 
highest  developments  of  the  great  tribe  of  herbivorous  quadru- 
peds. 

The  extension  of  railways  over  the  whole  country  about  the 
middle  of  the  century,  and  the  fact  that,  as  the  herds  dimin- 
ished buffalo  skins  became  more  valuable,  led  to  its  rapid 
extermination ;  and  at  the  present  time  only  a  small  and  d^\'in- 
dling  herd  exists  in  the  Yellowstone  Park,  and  another  in 
north-western  Canada. 

Even  more  remarkable  has  been  the  disappearance  of  the 
passenger  pigeon  (Ectopistcs  migratoria),  so  called  from  its 
great  powers  of  flight  and  its  migration  in  vast  flocks  all  over 
Xorth  America.  The  population  of  this  bird  was  almost  in- 
credibly great,  as  described  by  the  American  ornithologists 
Audubon  and  Wilson  in  the  early  part  of  the  nineteenth  cen- 


HEREDITY,  VARIATIOX  125 

tiiry.  It  inhabited  the  whole  of  the  wooded  parts  of  Xorth 
America  from  Mexico,  within  the  tropic?,  to  the  northern 
shores  of  Ilndson's  Bay,  and  its  former  history  is  now  tlie  more 
interesting,  because  it  has  already  become  a  creature  of  the 
past.  In  the  American  periodical.  The  Auk,  of  last  year,  is 
the  following  note : 

''The  Passenger  Pigeox  —  only  One  Pair  left. —  I  have 
taken  a  special  interest  in  the  remaining  birds  belonging  to  the 
Milwaukee  and  Cincinnati  flocks  which  have  been  in  confinement 
for  many  years.  In  my  last  remarks  on  the  species  (Auk,  1908, 
p.  18)  I  stated  that  the  remnants  of  these  flocks  then  numbered 
but  seven  birds,  with  little  or  no  chance  of  further  reproduction. 
The  number  is  now  reduced  to  a  single  pair,  and  doubtless  the 
months  are  numbered  when  this  noble  bird  must  be  recorded  as 
extinct. —  Ruthven  Deane,  Chicago,  111.'' 

In  view  of  the  above  statement  it  ^\i\\  be  both  interesting 
and  instructive  to  state  briefly  what  were  the  facts  as  to  the 
numbers  of  these  birds  about  a  hundred  years  ago  (1811). 
Alexander  Wilson  gives  the  following  account  in  his  American 
Ornithology : 

"  The  roosting-places  are  always  in  the  woods,  and  sometimes 
occupy  a  large  extent  of  forest.  "When  they  have  occupied  one  of 
these  places  for  some  time  tlie  appearance  it  presents  is  surprising. 
The  ground  is  covered  to  the  depth  of  several  inches  with  their 
dung;  all  the  tender  grass  and  underwood  destroyed;  the  surface 
strewed  with  large  limbs  of  trees  broken  down  by  the  weight  of  tlie 
birds  collecting  one  above  another ;  and  the  trees  themselves  for 
thousands  of  acres  killed  as  completely  as  if  girdled  with  an  axe. 
The  marks  of  their  desolation  remain  for  many  years.  When  these 
roosts  are  first  discovered,  the  inhabitants  from  considerable  dis- 
tances visit  them  in  the  night,  with  guns,  clubs,  long  poles,  pots  of 
sulphur,  and  various  other  engines  of  destruction.  In  a  few  liours 
they  fill  many  sacks  and  load  horses  with  them. 

"The  breeding-place  differs  from  the  roost  in  its  greater  extent. 
In  the  western  countries,  viz.,  the  States  of  Ohio.  Kentucky,  and 
Indiana,   these  are  genei-allv   in   backwoods,  and  often  extend   in 


126  THE  WORLD  OF  LIFE 

neai'h^  a  straight  line  across  the  country  for  a  great  distance.  Not 
far  from  Shelby villc;,  in  the  State  of  Kentucky,  about  five  years  ago, 
there  was  one  of  these  breeding-places  which  stretched  through  the 
woods  in  nearl}^  a  north  and  south  direction,  was  several  miles  in 
breadth,  and  was  said  to  be  upwards  of  forty  miles  in  extent.  In 
this  tract  almost  everv  tree  was  furnished  with  nests  wherever  the 
branches  could  accommodate  them.  The  pigeons  made  their  first 
appearance  there  about  the  10th  of  April,  and  left  it  altogether 
with  their  young  before  the  25th  of  May.  As  soon  as  the  young 
were  fully  grown,  and  before  they  left  the  nests,  numerous  parties 
of  the  inhabitants  from  all  parts  of  the  adjacent  country  came  with 
wagons,  axes,  beds,  cooking  utensils,  many  of  them  accompanied  by 
the  greater  part  of  their  families,  and  encamped  for  several  days  at 
this  immense  nursery.  Several  of  them  informed  me  that  the  noise 
was  so  great  as  to  terrify  their  horses,  and  that  it  was  difficult  for 
one  person  to  hear  another  speak  without  bawling  in  his  ear.  The 
ground  was  strewed  wath  broken  limbs  of  trees,  eggs,  and  young 
squab  pigeons,  which  had  been  precipitated  from  above,  and  on 
which  herds  of  hogs  were  fattening.  Hawks,  buzzards,  and  eagles 
were  sailing  about  in  great  numbers,  and  seizing  the  squabs  from 
the  nests  at  pleasure,  while  from  twenty  feet  upwards  to  the  top 
of  the  trees  the  view  through  the  woods  presented  a  perpetual  tumult 
of  crowding  and  fluttering  multitudes  of  pigeons,  their  wings  roar- 
ing like  thunder,  mingled  with  the  frequent  crash  of  fallen  timber ; 
for  now  the  axe-men  were  at  work,  cutting  down  those  trees  that 
seemed  to  be  most  crowded  with  nests,  and  contrived  to  fell  them 
in  such  a  manner  that  in  their  descent  they  might  bring  down 
several  others,  by  which  means  the  falling  of  one  large  tree  some- 
times produced  200  squabs,  little  inferior  in  size  to  the  old  ones 
and  almost  one  heap  of  fat.  It  was  dangerous  to  walk  under  these 
flying  and  fluttering  millions  from  the  frequent  fall  of  large 
branches,  broken  down  by  the  weight  of  the  multitudes  above,  and 
which  in  their  descent  often  destroyed  numbers  of  the  birds  them- 
selves, while  the  clothes  of  those  traversing  the  woods  were  com- 
pletely covered  with  the  excrements  of  the  pigeons. 

"  I  passed  for  several  miles  through  this  same  breeding-place, 
where  every  tree  was  spotted  with  nests,  the  remains  of  those  above 
described.  In  manv  instances  I  counted  upwards  of  ninety  nests 
in  a  single  tree;  but  the  pigeons  had   abandoned  this  place  for 


HEREDITY,  VAEIATIOK  127 

another,  sixty  or  eighty  miles  oIT,  towards  Green  river,  where  they 
were  said  at  tliat  time  to  he  equally  numerous.  From  the  great 
numbers  that  were  continually  passing  over  our  heads  to  or  from 
that  quarter,  I  had  no  doubt  of  the  truth  of  this  statement.  The 
mast  had  been  chiefly  consumed  in  Kentucky;  and  the  pigeons, 
every  morning  a  little  before  sunrise,  set  out  for  the  Indiana  terri- 
tory, the  nearest  part  of  which  w^as  about  sixty  miles  distant. 
Many  of  these  returned  before  ten  o'clock,  and  the  great  body 
generally  appeared  on  their  return  a  little  after  noon.  I  had  left 
the  public  road  to  visit  the  remains  of  the  breeding-place  near 
Shelbyville,  and  was  traversing  the  woods  with  my  gun,  on  my  way 
to  Frankfort,  when  about  ten  o'clock,  the  pigeons  which  I  had 
observed  flying  the  greater  part  of  the  morning  northerly,  began 
to  return  in  such  immense  numbers  as  I  never  before  had  witnessed. 
Coming  to  an  opening  by  the  side  of  a  creek  called  the  Benson, 
where  I  had  a  more  uninterrupted  view,  I  was  astonished  at  their 
appearance;  they  were  flying  with  great  steadiness  and  rapidity,  at 
a  height  beyond  gunshot,  in  several  strata  deep,  and  so  close  to- 
gether that,  could  shot  have  reached  them  one  discharge  could  not 
have  failed  bringing  down  several  birds.  From  right  to  left  as  far 
as  the  eye  could  reach,  the  breadth  of  this  vast  procession  extended, 
seeming  everywhere  equally  crowded.  Curious  to  determine  how 
long  this  appearance  would  continue,  I  took  out  my  watch  to  note 
the  time,  and  sat  down  to  observe  them.  It  was  then  half-past  one ; 
I  sat  for  more  than  an  hour,  but  instead  of  a  diminution  of  this 
prodigious  procession  it  seemed  rather  to  increase,  both  in  numbers 
and  rapidity,  and  anxious  to  reach  Frankfort  before  night,  I  rose 
and  went  on.  About  four  o'clock  in  the  afternoon  I  crossed 
Kentucky  river,  at  the  town  of  Frankfort,  at  which  time  the  living 
torrent  above  my  head  seemed  as  numerous  and  extensive  as  ever. 
Long  after  this  I  observed  them  in  large  bodies  that  continued  to 
pass  for  six  or  eight  minutes,  and  these  again  were  followed  by 
other  detached  bodies,  all  moving  in  the  same  south-east  direction 
till  after  six  o'clock  in  the  evening.  The  great  breadth  of  front 
which  this  mighty  multitude  preserved  would  seem  to  intimate  a 
corresponding  breadth  of  their  breeding-place,  wdiich,  by  several 
gentlemen  w^ho  had  lately  passed  through  part  of  it,  was  stated  to 
me  as  several  miles." 


128  THE  WOr.LD  OF  LIFE 

Wilson  then  gives  a  rongli  calciilation  of  the  probahle  num- 
bers of  this  great  flight  of  pigeons,  and  comes  to  the  conclusion 
that  its  whole  length  was  240  miles,  and  that  the  number  of 
birds  must  have  been  considerably  more  than  2000  millions. 
If  each  pigeon  consumed  only  half  a  pint  of  food  daily,  the 
quantity  would  amount  to  over  IT  millions  of  bushels  daily. 
Audubon,  who  went  throu2;h  the  same  country   about  twentv 

7  ~  1-1/ 

years  later,  confirms  Wilson's  account  in  every  essential  part ; 
and  the  language  of  the  former  is  so  simple  and  restrained, 
that  there  is  evidently  no  attempt  to  exaggerate  what  he  wit- 
nessed and  was  informed  of  by  many  independent  observers. 
Waterton,  with  his  usual  scepticism  as  to  the  observations  of 
other  naturalists,  treats  the  whole  narrative  as  gross  exaggera- 
tion or  fabrication ;  on  which  the  late  Professor  Alfred  Xewton 
remarks,  that  the  critic  would  probably  have  been  less  severe 
had  he  known  that,  150  years  earlier,  these  pigeons  so  swarmed 
and  ravaged  the  colonists'  crops  near  Montreal,  that  a  bishop 
of  his  own  Church  was  constrained  to  exorcise  them  with  holy 
water  as  if  they  had  been  demons.  Professor  Xewton  adds 
that  the  rapid  and  sustained  flight  of  these  pigeons  is  as  well 
established  as  their  former  overwhelming  abundance,  birds  hav- 
ing been  killed  in  the  State  of  Xew  York  whose  crops  contained 
undigested  grains  of  rice  that  must  have  been  not  long  before 
plucked  and  swallowed  in  South  Carolina  or  Georgia.  The 
passenger  pigeon  has  several  times  been  shot  in  Great  Britain, 
and  Professor  Xewton  believes  that  some  of  these  crossed  the 
Atlantic  unassisted  by  man. 

Considering  the  vast  multitudes  of  these  birds  in  a  state  of 
nature,  notwithstanding  the  variety  of  birds  of  prey  in  Xorth 
America,  together  with  its  unequalled  powers  of  flight,  it  must 
be  classed  as  one  of  the  finest  examples  of  what  DarAvin  termed 
"  dominant  species,"  and  may  also  be  considered  as  the  highest 
development  of  the  special  type  of  bird-life  manifested  in  the 
order  Columbse  or  Pigeons ;  and  it  will  doubtless,  by  future 
generations  of  bird-lovers,  be  counted  as  a  blot  upon  the  boasted 
civilisation  of  the  nineteenth  century  that,  in   its  mad  greed 


HEREDITY,  VARIATION 


129 


for  wealth,  it  should  have  so  devastated  a  whole  continent  as 
not  to  leave  room  in  it  for  the  continued  existence  of  such 
grand  and  beautiful  life-fomis  as  the  bison  and  passenger 
pigeon. 

Equally  remarkable,  perhaps,  is  the  Norwegian  lemming,  a 
little  animal  somewhat  larger  than  our  short-tailed  field-mouse, 


Fig.  12. —  The  Lemming   {Myodes  lemmus). 

but  with  a  tail  only  half  an  inch  long.  This  creature  is  always 
abundant  in  Lapland  and  northern  Scandinavia,  but  only  ex- 
traordinarily so  at  long  intervals,  when  favourable  conditions 
lead  to  its  almost  incredible  multiplication.  At  intervals  of 
from  ten  to  twenty-five  years  a  great  army  of  them  appears, 
which  devours  every  green  thing  in  its  path.  Great  bands 
descending  from  the  highlands  of  Lapland  and  Finland  march 
in  parallel  lines  about  3  feet  apart,  never  turning  aside,  cross- 
ing lakes,  and  rivers,  and  even  eating  through  com  and  hay- 
stacks  when    these    cross    their    path.     The    following    recent 


130  THE  WOELD  OF  LIFE 

statement  of  the  ascertained  facts  as  to  these  strange  migra- 
tions —  from  the  work  on  Mammals  by  the  late  Sir  H.  Flower 
and  E.  Lydekker  —  will  prove  interesting: 

"  The  -usual  dwelling-place  of  the  Lemmings  is  in  the  highlands 
or  fells  of  the  great  central  mountain  chain  of  Norway  and  Sweden. 
South  of  the  Arctic  circle,  they  are,  under  ordinary  circumstances, 
exclusively  confined  to  the  plateaus  covered  with  dwarf  birch  and 
juniper  above  the  conifer  region,  though  in  Tromso  and  Finmarken 
they  occur  in  all  suitable  places  down  to  the  level  of  the  sea.  The 
nest  is  found  under  a  tussock  of  dry  grass  or  a  stone,  constructed  of 
dry  straws  and  usually  lined  with  hair.  The  number  of  young  in 
each  nest  is  generally  five,  and  at  least  two  broods  are  produced 
annually.  Their  food  is  entirely  vegetable,  especially  grass  roots 
and  stalks,  shoots  of  the  birch,  reindeer-lichen  and  mosses,  in  search 
of  which  they  form  in  winter  long  galleries  through  the  turf  or 
under  the  snow.  They  are  restless,  courageous,  and  pugnacious 
little  animals.  AMien  suddenly  disturbed,  instead  of  trying  to  es- 
cape, they  will  sit  upright,  with  their  back  against  a  stone  or  other 
object,  hissing  or  showing  fight  in  a  very  determined  manner. 
(See  Fig.  12.) 

"  The  circumstance  which  has  given  more  popular  interest  to 
the  Lemming  than  to  a  host  of  other  species  of  the  same  order  of 
animals  is  that  certain  districts  of  the  cultivated  lands  of  iSTorway 
and  Sweden,  where  in  ordinary  circumstances  they  are  quite  un- 
known, are  occasionally  and  at  very  uncertain  intervals,  varying 
from  five  to  twent}^  or  more  years,  literally  overrun  by  an  army  of 
these  little  creatures,  which  steadily  and  slowly  advance,  always  in 
the  same  direction,  and  regardless  of  all  obstacles,  swimming  across 
rivers  and  even  lakes  of  several  miles  in  breadth,  and  committing 
considerable  devastation  on  their  line  of  march  by  the  quantity  of 
food  they  consume.  In  their  turn  they  are  pursued  and  harassed 
by  a  crowd  of  beasts  and  birds  of  prey,  as  bears,  wolves,  foxes,  dogs, 
wild  cats,  stoats,  weasels,  hawks,  and  owls,  and  are  never  spared  by 
man;  even  the  domestic  animals  not  usually  predaceous,  as  cattle, 
goats,  and  reindeer,  are  said  to  join  in  the  destruction,  stamping 
them  to  the  ground  with  their  feet,  and  even  eating  their  bodies. 
Numbers  also  die  from  diseases  apparently  produced  by  overcrowd- 
ing.    None  ever  return  by  the  course  over  which  they  have  come. 


HEEEDITY,  VARIATION  131 

and  the  onward  march  of  the  survivors  never  ceases  until  they  reach 
the  sea,  into  which  they  plunge,  and  swimming  outwards  in  the 
same  direction  as  before,  perish  in  the  waves.  ...  So  extraor- 
dinary was  the  sudden  appearance  of  these  vast  bodies  of  Lem- 
mings to  the  Norwegian  peasants,  that  they  supposed  they  must 
have  fallen  from  tiie  clouds. 

"  The  principal  really  ascertained  facts  regarding  these  migra- 
tions seem  to  be  as  follows :  When  a  combination  of  favourable 
circumstances  has  occasioned  a  great  increase  in  the  numbers  of 
Lenmiings  in  their  ordinary  dwelling-places,  a  movement  neces- 
sarily occurs  at  the  edge  of  the  elevated  plateau,  and  a  migration 
towards  the  low-lying  land  begins.  The  whole  body  slowly  moves 
forward,  advancing  in  the  same  general  direction  in  which  they 
started,  but  following  more  or  less  the  course  of  the  great  valleys. 
They  only  travel  by  night,  and  they  also  stay  in  congenial  places 
for  weeks  or  months,  so  that,  with  unaccustomed  abundance  of 
food,  notwithstanding  all  the  destructive  influences  to  which  they 
are  exposed,  they  multiply  excessively  during  their  journey,  having 
families  still  more  numerous  and  more  frequently  than  in  their 
usual  homes.  The  progress  may  last  from  one  to  three  years,  ac- 
cording to  the  route  taken  and  the  distance  to  be  traversed  until 
the  sea  coast  is  reached,  which,  in  a  country  so  surrounded  by 
water  as  the  Scandinavian  peninsula,  must  be  the  ultimate  goal  of 
such  a  Journey.  This  may  be  either  the  Atlantic  or  the  Gulf  of 
Bothnia,  according  as  the  migration  has  commenced  from  the  west 
or  east  side  of  the  elevated  plateau.  Those  that  finally  perish  in 
the  sea  are  only  acting  under  the  same  blind  impulse  which  has 
led  them  previously  to  cross  smaller  pieces  of  water  with  safety." 

The  strange  history  of  these  small  creatures,  besides  showing 
the  enormous  powers  of  increase  in  various  types  of  life,  also 
furnishes  us  with  a  fine  example  of  adaptation  to  what  would 
be,  to  most  animals,  extremely  adverse  conditions  —  high 
plateaus  within  or  bordering  on  the  Arctic  circle,  with  its 
intense  cold,  its  long  periods  of  darkness,  buried  in  snow  in 
winter  and  with  a  scantv  and  stunted  vegetation.  Yet  thev 
appear  to  have  a  most  enjoyable  existence,  and  would  evidently 
be  able  to  overrun  and  occupy  a  much  larger  extent  of  sim- 


132  THE  WORLD  OF  LIFE 

ilarly  inhospitable  country  did  such  exist  in  their  vicinity; 
while  in  more  fertile  lands,  with  a  milder  climate  and  more 
luxuriant  vegetation,  they  rapidly  become  extinct  through  dis- 
ease or  the  attacks  of  enemies. 

In  Mr.  W.  II.  Hudson's  most  interesting  volume,  A  Nat- 
uralist in  La  Plata,  he  gives  an  account  of  a  very  similar  rapid 
increase  of  field-mice,  under  extremely  different  conditions,  in 
the  chapter  entitled  A  Wave  of  Life.  In  a  concluding  pas- 
sage he  so  clearly  summarises  the  whole  course  of  events  that 
I  here  extract  it :  — 

"  Cover  and  food  without  limit-  enabled  the  mice  to  increase  at 
such  an  amazing  rate,  that  the  ordinary  checks  interposed  by  pred- 
atory species  were  for  a  while  inappreciable.  But  as  the  mice 
increased  so  did  their  enemies.  Insectivorous  and  other  species 
acquired  the  habits  of  owls  and  weasels,  preying  exclusively  on 
them;  while  to  this  an  innumerable  array  of  residents  was  shortly 
added  multitudes  of  wandering  birds  coming  from  distant  regions. 
'No  sooner  had  the  herbage  perished,  depriving  the  little  victims  of 
their  cover  and  food,  than  the  effects  of  the  war  became  apparent. 
In  autumn  the  earth  so  teemed  with  them  that  one  could  scarcely 
walk  anywhere  without  treading  on  mice ;  while  out  of  every  hollow 
weed-stalk  lying  on  the  ground  dozens  could  be  shaken;  but  so 
rapidly  had  they  been  devoured  by  the  trained  army  of  persecutors 
that  in  spring  it  was  hard  to  find  a  survivor  even  in  the  barns  and 
houses.  The  fact  that  species  tend  to  increase  in  a  geometrical 
ratio  makes  these  great  and  sudden  changes  frequent  in  man}^  parts 
of  the  earth;  but  it  is  not  often  that  they  present  themselves  so 
vividly  as  in  the  foregoing  instance,  for  here,  scene  after  scene  in 
one  of  l^ature's  silent,  passionless  tragedies,  myriads  of  highly 
organised  beings  rising  into  existence  only  to  perish  almost  imme- 
diately, scarcely  a  hard-pressed  remnant  surviving  to  continue  the 
species." 

It  may,  however,  be  concluded  that  not  thus  are  species 
exterminated  in  any  region  that  remains  suitable  for  their 
existence.  Long  before  they  approach  extinction,  the  very 
scarcity  of  them  drives  away,  one  after  another,  the  crowd  of 


HEEEDITY,  YAEIATION"  133 

enemies  whicli  had  been  attracted  by  their  inordinate  num- 
berSj  till  the  former  balance  of  life  is  restored,  and  the  rapid 
powers  of  increase  of  the  sufferers  soon  restores  them  to  their 
normal  population.  It  is  against  the  adverse  powers  of  inor- 
ganic nature  that  speedy  reproduction  is  such  a  safe-guard. 
When  fire  or  flood,  droughts  or  volcanic  outbursts  have  de- 
stroyed animal  life  over  wide  areas,  the  few  survivors  on  the 
margin  of  the  devastated  area  are  able  to  keep  pace  with 
renewed  vegetation  and  again  stock  the  land  with  its  former 
variety  of  living  things. 

The  facts  outlined  in  the  present  chapter,  of  abundant  and 
ever-present  variability  with  enormous  rapidity  of  increase, 
furnish  a  sufficient  reply  to  those  ill-informed  writers  who  still 
keep  up  the  parrot-cry  that  the  Darwinian  theory  is  insuffi- 
cient to  explain  the  formation  of  new  species  by  survival  of 
the  fittest. 

They  also  serve  to  rule  out  of  court,  as  hopelessly  inefficient, 
the  modern  theories  of  ^'  mutation  "  and  "  mendelism,''  which 
depend  upon  such  comparatively  rare  phenomena  as  "  sports  '' 
and  abnormalities,  and  are,  therefore,  ludicrously  inadequate 
as  substitutes  for  the  Darwinian  factors  in  the  world-wide  and 
ever-acting  processes  of  the  preservation  and  continuous  adap- 
tation of  all  living  things.  The  phenomena  upon  which  these 
theories  are  founded  seem  to  me  to  be  mere  insifmificant  bve- 
products  of  heredity,  and  to  be  essentially  rather  self-destruc- 
tive than  preservative.  They  form  one  of  nature's  methods  of 
getting  rid  of  abnormal  and  injurious  variations.  The  per- 
sistency of  Mendelian  characters  is  the  veiy  opposite  of  what 
is  needed  amid  the  ever-changing  conditions  of  nature.^ 

1  A  critical  examination  of  these  theories  is  gjiven  in  Mr.  G.  Archdall 
Reid's  recent  work,  The  Principles  of  Heredity.  There  is  also  a  shorter  and 
more  popular  criticism  in  the  Introduction  to  Professor  E.  B.  Poiilton's 
Essays  on  Evolution  (1908). 


CHAPTER    VIII 

ILLUSTRATIVE    CASES    OF   NATURAL    SELECTION    AND   ADAPTATION 

We  have  now  learnt  something  of  the  great  features  of  the 
^'  world  of  life  "  whose  origin,  development,  and  meaning  we 
are  seeking  to  comprehend ;  we  have  been  enabled  to  visualize 
its  enormous  extent,  its  almost  endless  diversity  of  form,  struc- 
ture, and  mode  of  existence;  the  vast  population  of  the  species 
that  compose  it,  especially  those  which  we  term  common. 
Further,  we  have  seen  something  of  the  way  in  which  large 
numbers  of  species  inhabit  the  same  area  intermingled  to- 
gether, which  they  are  enabled  to  do  by  each  being  adapted 
to  some  one  station  or  particular  kind  of  food  which  its  peculiar 
organisation  enables  it  to  utilise;  each  occupying,  as  it  were, 
a  special  place  in  the  economy  of  nature. 

We  have  also  learnt  something  of  the  three  great  factors  which 
are  essential  for  the  gradual  modification  of  species  into  new 
and  better  adapted  organisms  —  heredity,  variation,  and  enor- 
mous powers  of  increase,  leading  inevitably  to  a  struggle  for 
existence,  since  of  the  many  that  are  born  only  a  few  can 
possibly  survive.  We  are,  therefore,  now  prepared  to  exam- 
ine, so  far  as  we  are  able,  the  exact  method  of  Nature's  work 
in  species-production. 

One  of  the  difficulties  in  the  way  of  an  acceptance  of  con- 
tinuous evolution  through  variation  and  natural  selection  is, 
that  though  variation  may  be  fully  admitted,  and  though  great 
changes  of  climate  and  some  changes  of  land  and  sea  have 
occurred  in  the  human  period,  these  do  not  seem  to  have  led 
to  the  foraiation  of  new  species,  but  only  to  the  extinction, 
or  change  in  the  distribution,  of  a  few  of  them.  But  of  late 
years  naturalists,  having  pretty  well  exhausted  the  well-defined 
species  of  the  best-known  parts  of  the  world  —  Europe   and 

134 


CASES  OF  ADAPTATION  135 

iN'ortli  America  —  have  j^aid  more  attention  to  varieties,  and 
especially  to  those  characteristic  of  islands  or  other  well- 
marked  and  somewhat  isolated  districts. 

Having  been  much  struck,  some  forty  years  ago,  by  the  fact 
that  two  peculiar  beetles  are  found  in  Lundy  Island  (in  the 
Bristol  Channel),  another  in  Shetland,  while  some  peculiar 
forms  of  butterflies  and  moths  occurred  in  the  Isle  of  ^Alan,  I 
thought  it  would  be  interesting  to  collect  together  and  publish 
lists  of  all  the  species  or  varieties  of  animals  and  plants  whicli 
had  hitherto  been  found  only  in  our  Islands.  This  I  attempted 
when  writing  my  Island  Life  in  1880  and  several  specialists 
in  various  groups  were  kind  enough  to  draw  up  lists  for  me. 
These  were  revised  and  much  increased  in  the  second  and  third 
editions;  and  in  the  latter  (1902)  they  amounted  to  5  birds, 
14  fresh-water  fishes,  179  lepidoptera,  71  beetles,  122  land 
and  fresh-water  molluscs,  and  86  flowering  plants.  It  is  inter- 
esting to  note  that  of  these  latter  no  less  than  20  are  found  only 
in  Ireland,  where  the  insular  conditions  of  climate  that  may 
be  supposed  to  lead  to  modification  are  at  a  maximum.  Xo 
less  than  20  species  of  our  Mosses  and  27  of  our  Ilepaticse  are 
also  not  found  in  Europe,  though  a  few  of  them  are  (and  others 
may  be)   found  in  other  parts  of  the  world. 

As  there  is  no  doubt  that  our  islands  were  at  no  distant 
period  (in  a  geological  sense)  united  to  the  continent,  and 
that  since  their  separation  they  must,  through  the  influence 
of  the  Gulf  Stream  penetrating  around  and  among  them,  have 
acquired  a  milder,  moister,  and  a  more  uniform  climate,  it 
seems  quite  probable  that  a  considerable  proportion  of  these 
numerous  local  forms  are  actual  modifications  of  the  allied 
continental  forms  due  to  adaptation  to  the  changed  conditions. 

Since  my  book  was  published,  an  interesting  addition  to  the 
list  of  peculiar  birds  has  been  made  by  Dr.  Ernst  Ilartert,  in 
an  article  entitled  On  Birds  represented  in  the  British  Isles, 
by  peculiar  Forms.  In  this  list,  with  MSS.  additions  up  to 
the  end  of  1909,  Dr.  Hartert  enumerates  no  less  than  21  spe- 
cies, which  have  become  more  or  less  distinctly  modified  from 


136  THE  WOELD  OF  LIFE 

their  continental  allies.  These  include  a  distinct  crossbill  from 
the  highlands  of  Scotland,  all  our  British  titmice,  which  seem 
to  be  especially  modifiable,  and  several  others.  The  complete 
list  is  as  follows :  — 

1.  Pyrrhula   pyrrhula  pileata British  Bullfinch. 

2.  Turdus  musicus  clarkei "        Song-Thrush. 

3.  Pratincola   rubicola  hibernaeus "        Stonechat. 

4.  Garrulus    glandarius    riifitergum ....      "        Jay. 

5.  Loxia    curvirostra    scotica Scottish  Crossbill. 

6.  Carduelis  carduelis  britannicus British  Goldfinch. 

7.  Motacilla   flava  rayi Yellow  Wagtail. 

8.  "  alba  lugubris Pied  Wagtail. 

9.  Parus  major   newtoni British  Great  Titmouse. 


10. 
11. 
12. 
13. 
14. 


cieruleus    obscurus "        Blue  Titmouse. 

ater  britannicus "        Coal   Titmouse. 

palustris  dresseri "        Marsh  Titmouse. 

atricapillus    kleinschmidti . . . .     "        Willow  Titmouse, 
cristatus  scotica Scottish  Crested  Titmouse. 


15.  Aegithalus    caudatus    rosea British  Long-tailed   Titmouse. 

16.  Regulus   regulus   anglorum "        Goldcrest. 

17.  Sitta    europaea    britannica "        Nuthatch. 

18.  Certhia  familiaris  britannica "        Tree-creeper. 

19.  Erithacus  rubecula  melophilus "        Robin. 

20.  Troglodytes    troglodytes    pirtensis ,  .  St.  Kilda  Wren. 

21.  Cinclus    cinclus    britannicus British  Dipper. 

22.  Dendrocopus  major  anglicus "        Great  Spotted  Woodpecker 

23.  "  minor  comminutus "        Lesser       Spotted       Wood- 

pecker. 

24.  Lagopus   lagopus   scoticus Bed  Grouse. 

This  last  has  been  generally  treated  as  a  well-marked  species, 
but  Dr.  Hartert  considers  it,  with  all  the  others,  to  be  a  sub- 
species —  a  species  in  the  making.  It  is  certainly  a  very  inter- 
esting fact  that  so  many  of  our  familiar  birds  are  found  to 
present  constant  differences  from  their  continental  allies. 
Most  of  these  differences  are  of  colour  only,  but  some  diversity 
of  bulk  and  in  the  size  of  the  bill  indicate  the  commencement 
of  structural  modification;  and  these  various  differences  from 
the  nearest  continental  species  in  so  many  of  our  resident  birds 
seem  inexplicable  on  any  other  theory  than  that  they  are  adap- 
tations to  the  slight  but  undoubted  difference  of  climatical  con- 
ditions which  characterise  our  islands. 


CASES  OF  ADAPTATION  137 

In  confirmation  of  this  view,  a  few  cases  have  been  recorded 
in  which  nature  has  been  caught,  as  it  were,  at  work  in  the 
actual  formation  of  new  species  at  the  present  time.  The 
first  is  that  of  the  Porto  Santo  rabbits,  carefully  investigated 
by  Darwin.  In  the  history  of  an  early  Spanish  voyage  it  is 
recorded  that,  a  female  rabbit  having  had  a  litter  of  young 
on  board,  they  were  all  turned  loose  on  this  small  uninhabited 
island  near  Madeira.  This  was  about  1419,  and  from  these 
alone  the  island  became  fully  stocked,  and  remains  so  still, 
although  the  island  is  now  fairly  peopled.  Darwin  was  able 
to  examine  two  of  these  rabbits  preserved  in  spirits,  three 
others  in  brine,  and  two  alive  which  had  been  in  the  Zoological 
Gardens  for  four  years.  These  seven  specimens,  though  caught 
at  different  times,  closely  resembled  each  other,  they  were  all 
full  grown,  yet  they  were  very  much  smaller  than  English 
wild  rabbits,  being  little  more  than  half  the  weight,  and  nearly 
three  inches  less  in  length.  Four  skulls  of  the  Porto  Santo 
rabbits  diifered  from  those  of  English  vdld  rabbits  in  the  supra- 
orbital processes  of  the  frontal  bone  being  narrower;  but  they 
differed  considerably  in  colour,  the  upper  surface  being  redder, 
and  the  lower  surface  pale  grey  or  lead  colour  instead  of  white ; 
the  upper  surface  of  the  tail,  however,  was  reddish-brown  in- 
stead of  blackish-grey  as  in  all  wild  European  rabbits,  while 
the  tips  of  the  ears  had  no  black  edging,  as  our  rabbits  always 
have. 

We  have  here  a  very  remarkable  series  of  differences  in  size, 
colour,  and  even  in  the  form  of  the  skull ;  while  it  was  noticed 
at  the  Zoological  Gardens  that  they  were  unusually  wild  and 
active,  and  also  more  nocturnal  in  their  habits  than  common 
wild  rabbits.  In  this  case,  these  rabbits  would  certainlv  have 
been  described  as  a  distinct  species  if  they  had  been  found 
in  some  more  remote  country  to  which  it  was  certain  that  they 
had  not  been  introduced  by  man. 

Another  example  which  shows  nature  at  work,  this  time  in 
the  actual  process  of  "  selection  "  of  the  better  adapted  indi- 
viduals, occurred  quite  recently.     In  February   1898,   at  the 


138  THE  WORLD  OE  LIFE 

Brown  University,  Providence,  Rhode  Island,  after  a  very 
severe  storm  of  snow,  sleet,  and  rain,  136  common  sparrows 
were  found  benumbed  on  the  ground,  and  were  collected  and 
brought  to  the  Anatomical  Laboratory.  They  were  laid  on 
the  floor  of  a  warmed  room  to  see  if  any  of  them  were  alive, 
where  after  a  short  time  72  of  them  revived  while  64  perished. 
The  happy  thought  occurred  to  Professor  LI.  C.  Bumpus,  that 
here  was  an  opportunity  of  discovering  whether  there  were  any 
visible  characters  indicating  why  some  of  these  birds,  under 
exactly  similar  conditions,  w^ere  destroyed  while  others  sur- 
vived. He  therefore  made  a  very  minute  and  careful  exami- 
nation of  all  the  birds,  living  and  dead,  with  very  interesting 
results,  of  which  the  following  is  a  summary: 

(1)  Sex. —  About  two- thirds  were  males,  one-third  females. 
Of  the  former  51  lived,  36  died;  of  the  latter  21  lived,  28 
died,  showing  a  decided  superiority  of  the  males  in  resisting 
cold  and  wet. 

(2)  Size. —  Here  the  comparison  was  made  of  male  adult 
birds,  male  young,  and  females,  separately;  in  all  three  of 
these  groups  those  which  died  were  larger  than  those  which 
sundved.  The  difference  was  not  very  great,  but  it  was  clearly 
marked,  and  as  it  occurred  in  all  three  groups  it  could  not 
possibly  be  imputed  to  chance. 

(3)  Weight. —  This  gives  the  same  result  as  in  the  last  case, 
the  survivors  being  lighter  than  those  w^hich  died,  by  the  con- 
siderable proportion  of  one  twenty-fifth. 

(4)  Length  of  the  Sternum  (breast-bone). —  This  character 
gives  a  rather  unexpected  result,  those  birds  which  survived 
having  a  decidedly  longer  sternum  than  those  which  perished. 
The  difference  is  about  .013  (a  little  more  than  one-hundredth) 
of  the  total  length;  but  as  the  smaller  birds  on  the  whole 
survived,  these  evidently  had  their  sterna  proportionally  very 
long.  ]^ow  the  sternum  is  an  indication  of  the  size  of  the 
pectoral  muscles  w^hich  move  the  wings  in  flight.  The  sur- 
viving birds  therefore  were  those  that  could  fly  quickest  and 
longest,   and  this  probably  led   to  the  more   rapid   production 


CASES  OF  ADAPTATION  139 

of  animal  heat.  Another  advantage  would  be,  that  these 
muscles  being  larger  proportionally  there  would  be  less  ex- 
posure of  the  internal  organs  to  the  extreme  cold. 

The  result  of  this  interesting  experiment  is  almost  conclu- 
sive as  to  the  reality  of  natural  selection.  In  this  case  those 
which  actually  survived  one  of  nature's  most  common  tests  — 
exposure  to  severe  storms  —  and  which  must  be  presumed  to 
have  been  the  ''  fittest "  at  that  particular  time  and  place,  were 
found  to  differ  in  just  such  characters,  and  in  such  moderate 
proportions  as  have  been  found  to  occur  constantly  in  all  the 
commoner  species  of  birds,  as  well  as  of  all  other  animals.  It 
proves  also  that  such  small  variations  are,  as  Professor  Lloyd 
Morgan  terms  it,  of  "  survival  value,"  a  fact  which  is  con- 
stantly denied  on  purely  theoretical  grounds. 

It  will  perhaps  make  the  subject  a  little  clearer  if  I  here 
enumerate  briefly  the  exact  causes  which  must  have  been  at 
work  in  bringing  about  the  changes  in  the  rabbits  of  Porto 
Santo  during  the  four  and  a  half  centuries  that  had  elapsed 
from  the  time  they  were  turned  loose  upon  the  island  to  the 
period  when  Darwin  obtained  his  specimens.  The  island  has 
an  area  of  about  20  square  miles ;  it  is  very  hilly,  of  volcanic 
origin,  with  a  dry  climate  and  scanty  vegetation.  It  is  about 
26  miles  from  Madeira,  400  from  Africa,  and  250  from  the 
Canary  Islands.  The  powers  of  increase  of  rabbits  being  so 
great,  and  the  island  being  at  that  time  uninhabited,  they 
would  certainly  in  a  very  few  years  have  increased  to  so  great 
a  multitude  as  to  consume  all  the  available  vegetation.  As 
they  approached  to  these  numbers,  and  were  obliged  to  expose 
themselves  in  the  daily  search  for  food,  many  birds  of  prey 
from  the  larger  island,  and  probably  others  from  the  Canaries 
and  from  Africa  —  hawks,  buzzards,  falcons,  and  owls  — 
would  flock  to  this  hitherto  desert  island  to  feed  upon  them, 
and  would  rapidly  reduce  their  numbers. 

Up  to  this  time,  perhaps  not  more  than  a  dozen  or  twenty 
years  from  their  first  introduction,  they  would  have  varied  in 
size  and  colour  as  do  the  common  domesticated  rabbits  from 


140  THE  WOELD  OF  LIFE 

which  Darwin  thinks  they  w^ere  nndonbtedly  derived.     Their 
numerous  enemies  would  at  first  capture  the  larger,  more  bulky, 
and  slower-moving  individuals,  then  the  white  or  black  speci- 
mens, who  would  be  more  easily  seen  and  pounced  upon.     This 
process,  continuously  acting  for  a  few  generations,  would  result 
in  a  smaller  and  more  dusky-coloured  race.     The  continuous 
attack  persisting,  the  size  would  be  again  reduced,  and  the  most 
agile   and   rapid   in  movement   would   alone   survive.     There- 
after, the  nocturnal  habit  would  be  acquired  by  the  day-feeders 
being    almost   exterminated,    and   owls   would   probably   alone 
remain  as  formidable  enemies.     Lastly,  the  extreme  wildness, 
sensitiveness  to  danger,  perhaps  to  noise  or  movement  of  any 
kind,  would  be  developed,  while  the  reduction  of  the  supra- 
orbital process  may  perhaps  have  been  beneficial  by  reducing  the 
width   of  the   head,   and   thus   allowing  them   to   enter   small 
holes  in  the  rocks  more  rapidly;  or  it  may  possibly  be  con- 
nected with  the  more  nocturnal  habits.     We  thus  see  that  all 
the  changes  that  have  occurred  in  this  interesting  animal  have 
no  relation  whatever  to  mere  "  isolation,"  which  many  writers 
still  persist  in  claiming  as  a  vera  causa  of  specific  change,  but 
are  all  clearly  traceable  as  the  results  of  (1)  rapid  powers  of 
multiplication;    (2)    that   small  amount   of  variability  which 
we  know"  occurs  in  all  such  animals;  and  (3)  rigid  selection 
through  diurnal  and  nocturnal  birds  of  prey,  which  we  have 
seen  to  play  so  large  a  part  in  keeping  down  the  numbers  of 
the  passenger  pigeons  in  ISTorth  America,  the  lemming  in  Scan- 
dinavia, and  the  mice  in  La  Plata. 

The  two  cases  now  adduced,  showing  how  nature  actually 
works  in  the  production  of  slightly  modified  forms  through 
"  variation  "  and  ^^  survival  of  the  fittest  "  will,  I  think,  render 
the  process  of  species-formation  sufficiently  intelligible.  Very 
slight  inorganic  agencies  have  here  been  seen  at  work  —  in  one 
case  a  single  severe  storm,  in  the  other  a  change  to  an  isolated 
habitat  where  slightly  new  conditions  prevailed.  But  when 
in  the  course  of  those  periods  when  geological  changes  were 
most  actively   at  work,   larger   and  more  permanent  climatic 


CASES  OF  ADAPTATION  141 

changes  occurred,  or  when  more  marked  diversities  of  soil  and 
vegetation,  with  exposure  to  more  severe  competition,  were 
brought  about,  those  modifications  of  the  environment  ^vould 
inevitably  result  in  more  marked  and  more  varied  adaptations 
of  form,  structure,  or  habits,  bringing  about  what  we  every- 
where recognise  as  perfectly  distinct  species. 

In  the  present  work  I  do  not  propose  to  go  further  into  this 
matter,  which  has  been  treated  with  sufficient  detail  and  with 
copious  illustrations  in  my  Darwinism  and  other  works,  as 
well  as  in  Darwin's  classical  volumes.  The  Origin  of  Species 
and  Animals,  and  Plants  under  Domestication.  I  will  there- 
fore now  proceed  to  an  account  of  some  of  those  broader  aspects 
of  adaptation  in  the  organic  world,  which,  so  far  as  I  am  aware, 
have  hitherto  received  little  attention. 

Some  Aspects  of  Organic  Adaptation 

Though  such  a  very  obvious  fact,  it  is  not  always  kept  in 
mind,  that  the  entire  animal  world,  in  all  its  myriad  manifes- 
tations, from  the  worm  in  the  soil  to  the  elephant  in  the  forest, 
from  the  blind  fishes  of  the  ocean  depths  to  the  soaring  sky- 
lark, depends  absolutely  on  the  equally  vast  and  varied  vege- 
table world  for  its  very  existence.  It  is  also  tolerably  clear, 
though  not  quite  so  conclusively  proved,  that  it  is  on  the  over- 
whelming variety  of  plant  species,  to  which  we  have  already 
called  attention,  that  the  corresponding  variety  of  animal  spe- 
cies, especially  in  the  insect  tribes,  has  been  rendered  possible. 

This  will  perhaps  be  better  seen  by  a  reference  to  one  of 
the  best-known  cases  of  general  adaptation,  which,  because  so 
common  and  obvious,  is  often  overlooked  or  misunderstood. 
All  lovers  of  a  garden  are  apt  to  regard  as  an  unmitigated  evil 
those  swarms  of  insects  which  attack  their  plants  in  spring,  and 
in  recurrent  bad  years  become  a  serious  nuisance  and  commit 
widespread  devastation.  At  one  time  the  buds  or  leaves  of 
their  fruit  trees  swarm  with  various  kinds  of  caterpillars,  while 
at  others  even  the  oak  trees  are  so  denuded  of  their  leaves  as 
to  become  an  eyesore  in  the  landscape.     Many  of  our  common 


142  THE  WOKLD  OF  LIFE 

vegetables,  and  even  the  grass  on  our  lawns,  are  in  some  sea- 
sons destroyed  bj  swarms  of  wire-worms  which  feed  on  their 
roots.  Turnips,  radishes,  and  allied  plants  are  attacked  by 
the  turnip-fly,  a  small  jumping  beetle  whose  larva  lives  in  the 
leaf  itself,  and  w^hich  often  swarms  in  millions.  Then  there 
are  the  a2:>hides  and  froghoppers  on  our  roses  and  other  shrubs 
or  flowers,  and  grubs  which  attack  our  apples,  our  carrots, 
and  most  other  crops;  and  all  these  the  gardener  usually  re- 
gards under  the  general  term  "  blight,"  as  a  serious  blot  on 
the  face  of  nature,  and  wonders  why  such  harmful  creatures 
were  permitted  to  exist. 

Most  professional  gardeners  would  be  rather  surprised  to 
hear  that  all  these  insect-pests  are  an  essential  part  of  the  world 
of  life ;  that  their  destruction  would  be  disastrous ;  and  that 
without  them  some  of  the  most  beautiful  and  enjoyable  of  the 
living  things  around  us  would  be  either  seriously  diminished 
in  numbers  or  totally  destroyed.  He  might  also  be  informed 
that  he  himself  is  a  chief  cause  of  the  very  evil  he  complains 
of,  because,  by  growing  the  plants  the  insect-pests  feed  upon 
in  large  quantities,  he  provides  for  them  a  superabundance  of 
food,  and  enables  them  to  increase  much  more  rapidly  than 
they  would  do  under  natural  conditions. 

Let  us  now  consider  what  happens  over  our  whole  country 
in  each  recurring  spring.  At  that  delightful  season  our  gar- 
dens and  hedgerows,  our  orchards,  woods,  and  copses  are 
thronged  with  feathered  songsters,  resident  and  migratory,  en- 
gaged every  hour  of  the  day  in  building  their  nests,  hatching 
their  eggs,  or  feeding  and  guarding  their  helpless  offspring. 
A  considerable  proportion  of  these  —  thrushes,  warblers,  tits, 
finches,  and  many  others  —  are  so  prolific  that  they  have  two 
or  three,  sometimes  even  more,  families  every  year,  so  that 
the  young  birds  reared  annually  by  each  pair  varies  from  four 
or  five  up  to  ten  or  twenty,  or  even  more. 

Now,  when  we  consider  that  the  parents  of  these,  to  the 
number  of  perhaps  fifty  species  or  more,  are  all  common  birds, 
which  exist   in  our  islands   in  numbers   amounting   to   many 


CASES  OF  ADAPTATION  143 

raillions  each,  we  can  partially  realise  the  enormous  quantity 
of  insect-food,  required  to  rear  perhaps  five  or  ten  times  that 
number  of  young  birds  from  the  egg  up  to  full  growth.  Al- 
most all  of  the  young  of  the  smaller  birds,  even  when  their 
parents  are  seed-eaters,  absolutely  require  soft  insect-food,  such 
as  caterpillars  and  grubs  of  various  sorts,  small  worms,  or  such 
perfect  insects  as  small  spiders,  gnats,  flies,  etc.,  which  alone 
supjoly  sufficient  nourishment  in  a  condensed  and  easily  digest- 
ible form. 

Many  enthusiastic  observers,  by  means  of  hiding-places  near 
the  nests  or  by  the  use  of  field-glasses,  have  closely  watched  the 
whole  process  of  feeding  young  birds,  for  hours  or  even  for 
w^hole  davs,  and  the  results  are  extremelv  instructive.  The 
chiff-chaff,  for  example,  feeds  its  young  on  small  grubs  ex- 
tracted from  buds,  small  caterpillars,  aphides,  gnats,  and  small 
flies  of  various  kinds ;  in  a  nest  with  five  young,  the  hen-bird 
fed  them  almost  all  day  from  early  morning  to  sunset,  bringing 
mouthfuls  of  food  at  an  average  four  times  in  five  minutes. 
This  may  no  doubt  be  taken  as  typical  of  a  number  of  the 
smaller  warblers  and  allied  birds. 

Blue  tits,  with  a  larger  family,  worked  continuously  for 
sixteen  hours  a  day  at  midsummer,  bringing  about  two  thou- 
sand caterpillars  to  the  ravenous  young  birds,  who,  taking  the 
average  at  10  (and  they  sometimes  have  16)  would  swallow 
200  each  in  the  day.  A  pair  of  marsh  tits  were  observed  to 
feed  their  young  entirely  with  small  green  caterpillars,  and 
in  one  case  made  475  journeys  with  food  in  seventeen  hours. 

A  gold-crest  with  eight  young  brought  them  food  16  times 
in  an  hour  for  sixteen  hours  a  day.  A  wren  fed  its  young 
278  times  in  a  day.  Even  the  common  house-sparrow,  itself 
a  typical  seed-eater,  feeds  its  young  on  caterpillars  or  on  small 
insects  which  it  catches  on  the  wins:.  A  flvcatcher  was  ob- 
served  to  sit  on  a  dead  branch  of  an  ash  tree  near  her  nest, 
whence  by  short  flights  she  cauglit  small  flies,  etc.,  on  the 
wing,  bringing  a  mouthful  to  her  young  every  two  to  five  min- 
utes. 


144  THE  WORLD  OF  LIFE 

As  every  schoolboy  knows,  the  number  of  nests  is  very  great 
to  those  who  know  how  to  look  for  them,  some  being  found  in 
almost  every  wood,  copse,  or  hedgerow.  As  examples,  in  a 
small  copse  in  Herts,  nine  different  species  of  birds  had  nests 
with  young,  all  within  50  yards  of  each  other.  In  another 
case,  nests  of  a  tit,  a  flycatcher,  and  a  wood-wren  were  found 
within  10  to  15  yards  of  each  other.  In  the  case  of  many 
small  birds  the  whole  period,  from  hatching  the  eggs  to  that 
of  the  young  leaving  the  nest  is  only  two  weeks,  but  swifts 
require  from  a  month  to  six  weeks. 

It  must  be  remembered  that  the  birds  carefully  clean  out 
the  nest  after  every  meal,  and  in  wet  or  very  chilly  weather 
carefully  protect  their  young,  and  as  they  must  also  procure 
food  for  themselves,  it  is  evident  that  their  labours  at  this 
time  are  really  prodigious.  And  this  vast  destruction  of  in- 
sect-life goes  on  unchecked  for  several  months  together,  and 
the  supply  never  seems  to  fail.  When  the  parent  birds  leave 
the  nest  in  search  of  food  for  their  young,  they  may  be  seen 
to  fly  to  some  adjacent  bush  or  branch  of  a  tree,  hop  rapidly 
about  it,  and  then  perhaps  fly  off  to  another,  having  apparently 
decided  that  the  first  one  had  already  been  nearly  exhausted. 
But  in  the  few  minutes  of  their  absence  they  are  always  able 
to  fill  their  mouths  with  small  caterpillars,  flics,  grubs,  etc., 
and  return  to  the  nest,  not  only  from  morning  to  night  on  one 
day,  but  the  same  day  after  day,  for  at  least  a  fortnight  and 
often  much  longer,  till  their  first  brood  is  fully  fledged  and 
able  to  provide  for  themselves.  But  unless  the  numbers  of 
insects  and  their  larvse  were  enormous,  and  were  increased 
day  by  day  by  fresh  hatchings  from  the  egg  as  fast  as  they 
were  devoured,  hosts  of  these  young  birds  would  perish  of 
hunger  and  cold.  For  if  the  parents  had  to  range  far  away 
from  their  nests,  and  could  not  find  the  necessary  supply  so 
quickly  as  they  do,  the  young  birds  would  be  subject  to  attack 
from  some  of  their  numerous  enemies,  would  suffer  from  cold 
or  wet,  and  as  they  grew  older  would  often,  in  their  frantic 


CASES  OF  ADAPTATIOX  145 

struggles  with  each  other,  fall  out  of  the  nest  and  quickly 
perish. 

What  wonderful  perfection  of  the  senses  must  there  be  in 
these  various  parent  birds;  what  acuteness  of  vision  or  of 
hearing;  what  rapidity  of  motion,  and  what  powerful  instinct 
of  jDarental  love,  enabling  them  to  keep  up  this  high-pressure 
search  for  food,  and  of  watchfulness  of  their  nests  and  j^oung, 
on  the  continuance  of  which,  and  its  unfailing  success,  the 
very  existence  of  those  young  and  the  continuance  of  the  race 
depends.  But  all  this  perfect  adaptation  in  the  parent  birds 
would  be  of  no  avail  unless  the  insect  tribes,  on  which  alone 
most  of  them  are  obliged  to  depend,  were  as  varied,  as  abun- 
dant, and  as  omnipresent  as  they  actually  are ;  and  also  imless 
vegetation  were  so  luxuriant  and  abundant  in  its  growth  and 
so  varied  in  its  character,  that  it  can  always  supply  ample  food 
for  the  insects  without  suffering  any  great  or  permanent  injury 
to  the  individual  plants,  much  less  to  any  of  the  species. 

By  such  considerations  as  these  we  learn  that  what  we  call 
insect-pests,  when  they  are  a  little  more  abundant  than  usual 
in  our  gardens  and  orchards,  do  not  exist  for  themselves  alone 
as  an  apparently  superfluous  and  otherwise  useless  part  of  the 
great  world  of  life,  but  are,  and  must  always  have  been  through- 
out long  past  geological  ages,  absolutely  essential  for  the  origina- 
tion and  subsequent  development  of  the  most  wonderful, 
delightful,  and  beautiful  of  all  the  living  things  around  us  — 
our  garden  friends  and  household  pets,  and  sweet  singers  of 
the  woods  and  fields.  Without  the  myriad  swarms  of  insects 
everywhere  devouring  a  portion  of  the  new  and  luxuriant  vege- 
tation, the  nightingale  and  the  lark,  the  wren,  the  redbreast, 
and  the  fairy-like  tits  and  goldcrests  might  never  have  come 
into  existence,  and  if  the  supply  failed  would  now  disappear 
for  ever! 

The    Uses   of  Mosquitoes 

If  now  we  go  beyond  our  OAvn  country  and  see  how  birds 
fare  in  distant  lands,  we  find  the  key  to  many  of  the  secrets 


146  THE  WORLD  OF  LIFE 

of  bird-life  in  the  greater  or  less  abundance  of  insects  which 
supply  them  with  food  at  the  critical  season  of  their  lives 
when  they  have  to  supply  daily  and  hourly  food  to  their  newly- 
hatched  broods.  Amid  all  the  infinite  variety  of  the  insect 
world  there  is  probably  no  one  order  which  supplies  such  an 
enormous  quantity  of  food  to  birds  and  other  creatures  as  the 
two-winged  flies  (Diptera)  whose  larvx  are  the  maggots  which 
quickly  devour  all  kinds  of  dead  beasts  and  birds,  as  well  as 
all  kinds  of  putrefying  animal  matter ;  but  in  the  perfect  state 
these  insects  abound  in  such  swarms  as  also  to  supply  food  to 
whole  groups  of  fly-catching  birds.  And  among  these  no  well- 
marked  and  very  restricted  group  is  at  once  so  hateful  to 
mankind  and  so  delightful  to  birds  as  the  mosquitoes.  It  is 
commonly  supposed  that  these  particular  insect-pests  are  more 
especially  tropical;  but  though  they  are  no  doubt  very  abun- 
dant in  many  parts  of  the  tropics,  yet  their  fullest  develop- 
ment is  to  be  found  in  the  icy  plains  of  the  Far  Xorth,  espe- 
cially within  the  Arctic  circle  both  in  the  Eastern  and  Western 
hemispheres. 

Sir  William  Butler  in  his  w^orks  —  The  Wild  Lone  Land, 
and  others  on  Arctic  and  sub-Arctic  Xorth  America  —  de- 
scribes them  as  often  swarming  in  such  abundance  as  to  com- 
pletely obscure  the  sun  like  a  dense  thundercloud ;  and  they 
furnish  abundant  material  for  the  wildly  exaggerated  stories 
in  which  Americans  delight  —  such  as  the  serious  statement 
that  they  can  pierce  through  the  thickest  cow-hide  boots,  and 
that  an  Irishman,  seeking  protection  from  them  by  covering 
his  head  with  a  copper  kettle,  they  pierced  it  in  such  countless 
numbers  that  their  combined  strength  enabled  them  to  fly  away 
with  it! 

Our  best  and  most  instructive  writer  on  the  wonderful  bird- 
migrations  to  the  Arctic  regions  is  the  late  Mr.  Henry  See- 
bohm,  who  spent  two  seasons  there,  one  in  the  north-east  of 
Russia,  at  Ust-Zylma,  and  at  the  mouth  of  the  Petchora  River, 
far  within  the  Arctic  circle;  and  another  in  [N'orthern  Siberia, 
at  the  mouth  of  the  Yenesay  River.     He  tells  us,  that  — 


CASES  OF  xiDAPTxiTIOX 


147 


"  Birds  go  to  the  Arctic  regions  to  breed^  not  by  thousands  but 
by  millions.  The  cause  of  this  migration  is  to  be  found  in  the 
lavish  prodigality  with  which  Nature  has  provided  food.     Seed  or 


Fig. 

13.— 

Sh 

oo  t 

ing 

Wild 

Geese 

on 

the 

Pet- 

chora 

River 

at 

Ust- 

Zylma 

(May 

14 

,   18 

75). 

fruit-eating  birds  find  an  immediate  and  abundant  supply  of  cran- 
berries^ crowberries,  and  other  ground  fruit,  which  have  remained 
frozen  during  the  long  winter,  and  are  accessible  the  moment  the 
snow  has  melted,  while  insect-eating  birds  have  only  to  open  their 
mouths  to  fill  them  with  mosquitoes/'  ^ 

Among  the  larger  birds  that  come  early  to  "these  regions 
to  breed  are  two  species  of  wild  swans  and  the  bean  goose. 
So  early  as  10th  May  they  began  to  arrive,  passing  over  Ust- 
Zylma  (Lat.  G6^  N.)  in  flocks,  where,  by  constiiicting  a  shelter, 
Mr.  Seebohm  was  able  to  shoot  one.  Even  these  large  birds 
find  ample  food  on  the  tundra  to  breed  there ;  for  just  before 
leaving  the   country,   wdien   near   the   mouth   of  the   Petchora 

1  Siberia  in  Europe,  p.  296. 


148 


THE  WORLD  OF  LIFE 


Eiver,   he  saw  them   returning  southward  with  their  young. 
He  writes : 

"  I  had  not  gone  more  than  a  mile  when  I  heard  the  cackle  of 
geese ;  a  bend  of  the  river's  bed  gave  me  an  opportunity  of  stalking 
them,  and  when  I  came  within  sight  I  beheld  an  extraordinary  and 
interesting  scene.     One  hundred,  at  least,  old  geese,  and  quite  as 


Fig.  14. —  Geese  Moulting  as  they  migrate  South   over  the  Tundra    (July 

and  August ) . 

many  young  ones,  perhaps  twice  or  even  thrice  that  number,  were 
marching  like  a  regiment  of  soldiers.  The  vanguard,  consisting  of 
old  birds,  was  half-way  across  the  stream,  the  rear,  composed 
principally  of  goslings,  was  running  down  the  steep  bank  towards 
the  water's  edge  as  fast  as  their  young  legs  could  carry  them.  Both 
banks  of  the  river  where  the  geese  had  doubtless  been  feeding, 
were  strewn  with  feathers,  and  in  five  minutes  I  picked  up  a 
handful  of  quills.  The  flock  was  evidently  migrating  to  the 
interior  of  the  tundra,  moulting  as  it  went  along." 

This  species  retires  southwards  before  the  winter,  and  visits 
us  every  year  in  September  or  October  being  especially  abun- 


CASES  OF  ADAPTATIO:^ 


149 


dant  in  Ireland,  where  it 
is  said  to  be  found  in 
every  bog  and  marsh. 
On  the  Siberian  tundra 
it  no  doubt  feeds  largely 
on  the  abundant  berries, 
but  also,  of  course,  on 
the  food  it  finds  in 
swamps     and     river-mar- 


gms. 


Coming  back  to  our 
more  special  subject  of 
the  mosquitoes,  Mr.  See- 
bohm  writes  as  follows. 
After  describing  some  of 
his  early  excursions  after 
birds  or  their  nests  he 
adds: 


Fig.  15. —  Mr.  Seebohm  in  his  Mosquito 

Veil. 


"  That  day  (June  2nd)  I  recorded  in  my  journal,  with  many 
groans,  the  arrival  of  the  mosquitoes.  Horrid-looking  beasts,  with 
bodies  a  third  of  an  inch  long,  monsters,  the  Culex  damnabilis  of 
Eae,  with  proboscis  infernali  veneno  inunita.  I  foresaw  that  we 
should  have  opportunities  enough  to  study  the  natural  history  of 
these  blood-thirsty  creatures  to  our  heart's  discontent." 

About  a  month  later  he  writes  when  searching  for  eggs, 
properly  identified : 

"  Doubtless  the  proper  thing  to  have  done  would  have  been  to 
lie  down  and  watch  the  birds  on  to  their  nests;  but  to  become  tlie 
nucleus  of  a  vast  nebula  of  mosquitoes  is  so  tormenting  to  the 
nerves,  that  we  soon  came  to  the  conclusion  that  the  birds  had  not 
begun  to  breed,  and  that  it  was  no  use  martyrising  ourselves  to  find 
their  eggs.  The  mosquitoes  were  simply  a  plague.  Our  hats  were 
covered  with  them;  they  swarmed  upon  our  veils;  they  lined  with 
a  fringe  the  branches  of  the  dwarf  birches  and  willows;  they  cov- 
ered the  tundra  with  a  mist." 


150  THE  WORLD  OF  LIFE 

But  this  was  quite  at  the  beginning  of  the  season,  and  he 
adds: 

"  We  were  told  that  this  pest  of  mosquitoes  was  nothing  as  yet 
to  what  it  would  become  later.  '  Wait  a  while/  said  our  Job's 
comforter,  '  and  you  will  not  be  able  to  see  each  other  at  twenty 


"^mmi 


Fig.    16. —  Messrs.   Seebohm  and  Harvie-Brown  watching  Grey   Plover 

through  a  Cloud  of  Mosquitoes. 

paces  distance;  you  will  not  be  able  to  aim  with  your  gun,  for  the 
moment  you  raise  your  barrel  half-a-dozen  regiments  of  mosquitoes 
will  rise  between  you  and  the  sight.' '' 

And  Mr.  Seebohm  described  how  he  Avas  protected  by  india- 
rabber  boots  and  cavalrv  2:auntlets,  and  a  carefully  constructed 
cage  over  his  head,  without  which  he  never  dare  go  out  on 
the  tundra   (see  Fig.  15). 

Xow  this  Arctic  country,  beyond  the  limit  of  forests  and 
stretching  to  the  polar  ocean,  ^vhich  is  buried  for  eight  or  nine 
months  under  six  feet  thick  of  snow^,  is  yet,  during  its  short 
summer,  a  very  paradise  for  birds  of  all  kinds,  which  flock  to 
it  from  all  over  Europe  and  Central  Asia  in  order  to  breed 
and  to  rear  their  young;  and  it  is  very  largely,  and  for  many 
species  almost  exclusively,  this  very  abundance  of  mosquitoes 
and  their  larvae  that  is  the  chief  attraction.  In  Mr.  Seebohm's 
works,   already   quoted,   and   in   his   fine  volume  on  the   Geo- 


CASES  OF  ADAPTATiOxX  151 

graphical  Distribution  of  the  Plovers  and  allied  birds,  he  gives 
a  most  graphic  account  of  this  country  and  of  the  birds  flock- 
ing to  it,  which  is  worth  quoting,  as  few  people  have  any  ade- 
quate idea  of  what  the  greater  part  of  the  iirctic  regions  really 
are  in  summer.  After  describing  its  extent  and  boundaries, 
he  says: 

"  I  have  called  this  district  a  paradise,  and  so  it  is  for  two 
or  three  months  of  the  year.  Nowhere  else  in  the  whole  world  can 
you  find  such  an  abundance  of  animal  and  vegetable  life,  brilliant 
flowers,  birds  both  of  gay  plumage  and  melodious  of  song,  where 
perpetual  day  smiles  on  sea  and  river  and  lake.  For  eight  months 
or  more  (according  to  the  latitude)  every  trace  of  vegetable  life  is 
completely  hidden  under  a  thick  blanket  which  absolutely  covers 
every  plant  and  bush.  Far  as  the  eye  can  reach,  in  every  direction 
nothing  is  to  be  seen  but  an  interminable,  undulating  plain  of  white 
snow." 

Then  after  describing  the  few  animals  that  live  there  even 
during  the  wunter,  and  the  strange  phenomenon  in  May  of 
continuous  day  and  almost  perpetual  sunshine,  at  midday  hot 
enough  to  blister  the  skin,  yet  still  apparently  in  mid-winter 
so  far  as  the  snow  is  concerned,  he  goes  on  to  describe  what 
there  takes  place: 

"  The  disc  of  snow  surrounding  the  North  Pole  at  the  end  of 
May  extends  for  about  two  thousand  miles  in  every  direction  where 
land  exists,  and  is  melting  away  on  its  circumference  at  the  rate 
of  about  four  miles  an  hour,  and  as  it  takes  a  week  or  more  to  melt, 
it  is  in  process  of  being  melted  for  a  belt  of  several  hundred  miles 
wide  round  the  circumference.  This  belt  is  crowded  with  migratoiv 
birds  eager  to  push  forwards  to  their  breeding  grounds  —  hurrying 
on  over  the  melting  snow  so  long  as  the  south  wind  makes  bare 
places  soft  enough  to  feed  on,  but  perpetually  being  driven  back 
by  the  north  wind,  which  locks  up  their  food  in  its  ice-chest. 
.  .  .  In  watching  the  sudden  arrival  of  summer  on  the  Arctic 
circle,  both  in  the  valley  of  the  Petchora,  in  East  Eussia,  and  in 
the  valley  of  the  Yenesay,  in  Central  Siberia,  I  was  impressed  with 
the  fact  that  the  influence  of  the  sun  was  nearly  nothing,  while 


152 


THE  WOKLD  OF  LIFE 


that  of  the  south  wind  was  almost  everything.  The  great  annual 
battle  between  summer  and  winter  in  these  regions  is  the  one  event 
of  the  year:  it  only  lasts  a  fortnight,  during  which  a  cold  winter 
is  transformed  into  a  hot  sunmier." 

He  then  gives  a  most  interesting  account  of  the  breaking  up 
of  the  ice  on  the  great  north-flowing  rivers  till  they  become 
roaring  floods  of  muddy  water,  crowded  with  lumps  of  melted 
ice  of  all  shapes  and  sizes.  On  the  20th  May  he  had  just 
crossed  the  Petchora  to  Ust-Zylma,  over  ice  which  was  already 
cracking. 

"  It  was  past  midnight,  and  at  any  moment  the  crash  might 
come.     Cracks  running  for  miles,  with  a  noise  like  distant  thunder, 


Fig.  17. —  loe  Breaking  up  on  the 
Petchora  River. 


warned  us  that  a  mighty  power  was  all  but  upon  us,  a  force  which 
seemed  to  impress  the  mind  with  a  greater  sense  of  power  than 
even  the  crushing  weight  of  water  at  Niagara,  a  force  which  breaks 
up  the  ice  more  than  a  mile  wide,  at  least  tliree  feet  thick,  and 
weighted  with  another  three  feet  of  snow,  at  tlie  rate  of  a  hundred 


CASES  OF  ADAPTATIO]^ 


153 


miles  in  twenty-four  hours.  .  .  .  We  slept  for  a  couple  of 
hours,  when,  looking  out  of  the  window,  we  found  that  the  crash 
had  come;  the  mighty  river,  Petchora,  was  a  field  of  pack-ice  and 
ice-floes  marching  past  towards  the  sea  at  the  rate  of  six  miles  an 
hour.  We  ran  out  on  to  the  banks  to  find  half  the  inliabitants  of 
Ust-Zylma  watching  the  impressive  scene.'' 

A  week  later  he  writes : 

"  Winter  is  finally  vanquished  for  the  year,  and  the  fragments  of 
his  beaten  army  are  compelled  to  retreat  to  the  triumphant  music 


Fig.  18. —  Midsummer  on  the  Tundra,  at  the  Mouth  of  the  Petchora  River. 

of  thousands  of  song-birds,  amidst  the  waving  of  green  leaves  and 
the  illumination  of  gay  flowers  of  every  hue.  The  transformation 
is  perfect.  In  a  fortnight  the  endless  waves  of  monotonous  white 
snow  have  vanished,  and  between  the  northern  limit  of  forest  growtli 
and  the  shores  of  the  Polar  basin  smiles  a  fairy-land,  full  of  the 
most  delightful  little  lakes  and  tarns,  where  phalaropes  swim  about 
amongst  ducks  and  geese  and  swans,  and  upon  whose  margins  stints 
and  sandpipers  trip  over  the  moss  and  the  stranded  pond-weeds, 
feeding  upon  the  larvae  of  mosquitoes,  or  on  the  fermenting  frozen 
fruit  of  last  year's  autumn. 


154 


THE  WORLD  OF  LIFE 


"  It  is  incredible  how  rapidly  the  transformation  is  completed. 
Twelve  hours  after  the  snow  had  melted  the  wood-anemone  was  in 
flower,  and  twenty-four  hours  after  the  yellow  flowers  of  the  marsh- 
marigold  opened.  In  a  short  time  the  country  looked  like  an 
English  garden  run  wild.  On  the  Arctic  Circle  wild  onions,  wild 
rhubarb,  pansies,  Jacob's  ladder,  purple  anemones,  dwarf  roses,  and 
a  hundred  other  flowers  made  the  country  quite  gay ;  whilst  on  the 
tundras  wild-fruits  of  various  kinds  —  crowberry,  cranberry,  cloud- 
berry,  arctic   strawberry  —  were   blended  with   reindeer-moss   and 


Fig.  19. —  Sudden  Arrival  of  Birds  in  the  Arctic  Regions  at  the  End  of  May. 

other  lichens,  together  with  the  most  characteristic  flowers  of  an 
Alpine  flora  —  gentians,  saxifrages,  forget-me-nots,  pinks,  monks- 
hoods (both  blue  and  yellow),  and  sheets  of  the  Silene  acauUs, 
with  its  deep-red  flowers.  The  Alpine  rhododendron  was  replaced 
by  a  somewhat  similar  shrub.  Ledum  palustre;  but  the  flora,  on 
the  whole,  was  like  that  of  the  Engadine  brought  down  to  the  level 
of  the  sea. 

"  Although  the  first  rush  of  migratory  birds  across  the  Arctic 
Circle  was  almost  bewildering,  every  piece  of  open  water  and  every 
patch  of  bare  ground  swarming  with  them,  a  new  species  on  an 
average  arriving  every  two  hours  for  several  days,  the  period  of 


CASES  OF  ADAPTATION  155 

migration  lasted  more  than  a  month.  A^ery  little  migration  was 
observable  till  the  last  week  in  May,  but  during  the  next  fortnight 
the  migration  was  prodigious.  In  additions  to  enormous  numbers 
of  passerine  birds,  countless  flocks  of  geese,  swans,  and  ducks  ar- 
rived, together  with  a  great  many  gulls,  terns,  and  birds  of  prey. 
During  the  next  fortnight,  from  the  5th  to  the  19th  of  June,  fresh 
species  of  passerine  birds  continued  to  arrive,  and  the  main  migra- 
tion of  the  great  plover  family  took  place." 

One  of  the  objects  of  Mr.  Seebohm's  journey  to  the  Arctic 
regions  was  to  obtain  authentic  eggs  and  nests  of  the  grey 
plover.  He  found  several,  after  long  search.  They  were  all 
situated  in  depressions  on  a  slight  ridge  among  black  bog-lakes, 
and  each  had  three  or  four  eggs.  The  charming  little  i)icture 
on  the  next  page  shows  both  nest,  eggs,  and  young  birds. 

In  order  to  ascertain  approximately  how  many  species  of 
birds  visit  the  Arctic  regions  in  the  summer  breeding  season, 
I  have  made  rough  lists  of  all  those  enumerated  by  Mr. 
Seebohm  in  his  two  books,  Siberia  in  Europe  and  Siberia  in 
Asia,  and  find  that  they  amount  to  160  species.  This  is  very 
nearly  equal  to  the  whole  number  of  resident  and  migratory 
birds  which  breed  in  our  own  country  (about  ISO)  ;  but  they 
cannot  be  more  than  a  portion  of  the  species  that  actually 
migrate  to  the  Arctic  lands,  as  they  were  the  result  of  two 
visits  only  of  about  a  couple  of  months  each,  and  only  two  very 
limited  areas  were  explored.  My  friend,  Mr.  II.  E.  Dresser, 
who  also  knows  these  regions  personally  and  has  made  a  special 
study  of  their  birds,  has  been  so  good  as  to  make  an  enumera- 
tion of  all  the  birds  known  to  breed  in  the  Arctic  regions 
of  Europe  and  Asia,  and  he  finds  it  to  be  land  birds  81)  species, 
waders  and  aquatics  84  species,  equal  to  173  in  alL  Consider- 
ing how  vast  is  the  extent  of  the  country,  and  how  few  ornithol- 
ogists visit  it,  we  may  put  the  total  number  at  at  least  ISO, 
and  possibly  even  200  species. 

The  great  accumulation  of  bird-life  is,  however,  vividly  pic- 
tured by  Mr.  Seebohm,  and  it  is  clear  from  all  that  he  says  — 
as  well  as  bv  what  he  does  not  sav  —  that  the  vast  hordes  of 


156 


THE  WORLD  OF  LIFE 


mosquitoes  must  be  the  chief  support  of  the  innumerable  mil- 
lions of  young  birds  which  have  to  be  fed  here,  both  passerine 
and  Avading  birds.  Of  the  former  more  than  eighty  species 
are  named,  including  seven  buntings,  four  tits,  two  grosbeaks, 


Fig.  20. —  Grey  Plover's  Nest  and  Young  {8quatarola  helvetica). 


six  pipits,  eleven  warblers,  five  wagtails,  two  sparrows,  three 
woodpeckers,  the  beautiful  Avaxwing,  and  a  host  of  others, 
many  of  which  are  among  our  common  birds.  What  a  delight 
to  them  all  must  be  this  mish  northward  into  a  land  of  per- 
petual daylight,  swarming  with  the  most  nutritious  food,  fruits 
and  berries  for  the  parents,  inexhaustible  clouds  of  mosquitoes 


CASES  OF  ADAPTATION  157 

—  which  Mr.  Seebohm  tells  us  are  an  especially  large  kind 
with  bodies  a  third  of  an  inch  long  —  and  the  equal  myriads 
of  their  larvse  in  every  little  pond  or  water-hole,  as  well  as 
quantities  of  larger  worms  and  larva'.  The  extreme  discom- 
forts as  well  as  the  cost  of  a  journey  to  these  far  northern 
lands  are  so  great  that  very  few  bird-  or  insect-collectors  vi>ir 
them,  and  it  is  not  easy  to  obtain  direct  and  accurate  obser- 
vations as  to  the  actual  part  played  by  the  myriad  swarms  of 
mosquitoes  in  attracting  birds  from  almost  every  part  of  tlio 
northern  hemisphere  to  go  and  breed  there.  Mr.  H.  3^]. 
Dresser,  who  has  made  a  special  study  of  Palnearctic  birds  and 
their  eggs,  has,  however,  obtained  for  me  some  very  interesting 
information.     He  writes: 


"  Colonel  Feilden  tells  me  that  the  young  of  the  knot  are  fed 
chiefly  on  the  larvae  of  mosquitoes." 


He  has  also  sent  me  a  copy  of  the  following  interesting  letter 
from  an  American  ornithological  correspondent,  Mr.  E.  T. 
Seton :  — 

"  In  reply  to  your  recent  favour  I  beg  to  say,  that,  in  my 
forthcoming  book  on  a  canoe  journey  of  2000  miles  which  I  made 
to  the  Arctic  regions  in  1907,  I  am  setting  forth  at  great  length  the 
numbers,  virulence,  and  distribution  of  the  mosquitoes,  together 
with  observations  on  those  creatures  which  are  immune  from  their 
attacks.  ...  I  should  say  that  the  night-hawk  (Chordeiles 
virginianus)  is  the  most  active  enemy  of  this  insect,  feeding  on  it 
during  the  whole  season.  On  one  occasion  T  took  over  100 
mosquitoes  from  the  throat  of  one  of  these  night-hawks,  that  was 
carrying  them  home  to  feed  its  young.  Many  similar  observations 
have  been  recorded.  Next  in  importance  would  come  the  broad- 
billed  flycatchers  of  the  American  group  Tyrannidae,  and  the  more 
abundant  though  smaller  species  of  the  Mniotiltidse.  All  of  these 
I  have  seen  feeding  on  the  adult  mosquitoes.  Doubtless  all  of  our 
thrushes  do  the  same,  although  I  do  not  recall  any  positive  records. 
We  are  very  safe,  I  take  it,  in  cataloguing  all  of  our  small  birds 
as  enemies  of  the  mosquitoes  in  the  adult  form.  The  various 
small  wading  birds,  and  the  small  ducks  and  grebes,  are  believed 


158  THE  WORLD  OF  LIFE 

to  prey  on  the  larval  mosquitoes ;  but  doubtless  it  is  the  insects  and 
small  fish  that  are  to  be  credited  with  the  principal  destruction  in 
this  stage." 

From  his  personal  observations  Mr.  Dresser  says: 

"  I  believe  that  most  of  the  waders  feed  their  young  on  them 
(mosquitoes)  in  the  high  north.  In  north  Finland  and  Lapland 
I  found  the  small  birds  (warblers,  swallows,  etc.)  feeding  on 
mosquitoes,  and  the  snow  bunting  fed  its  young  on  them." 

There  is,  therefore,  a  concensus  of  evidence  as  to  the  pre- 
eminent attraction  afforded  by  these  insects  to  almost  all  birds 
which  breed  in  the  Arctic  regions. 

The  beautiful  view  on  the  opposite  page  gives  us  an  idea 
of  the  appearance  of  the  upland  tundra  along  the  shores  of 
the  Arctic  Ocean.  Here  the  southern  slopes  of  the  low  hills 
are  the  first  to  be  free  from  snow,  and  afford  an  abundant 
supply  of  last  year's  berries  to  the  earliest  migrants,  as  well 
as  a  variety  of  animal  food  for  aquatic  birds  on  the  adjacent 
sea-shores  in  favourable  situations. 

The  combined  physical  and  emotional  enjoyment  in  this 
birds'  paradise,  during  the  whole  of  the  Arctic  summer,  for 
so  large  a  number  of  species  of  birds  and  in  such  enormous 
multitudes,  is  probably  unequalled  in  any  other  part  of  the 
world;  and  we  have  the  satisfaction  of  knowing  that  it  is 
perhaps  the  only  example  of  Nature's  short-lived  but  annual 
pleasure-gardens  which  will  not  be  destroyed  or  rendered 
hideous  by  the  destructiveness  and  greed  of  civilised  man. 
When  much  of  the  beauty  and  luxuriance  of  nature  has  been 
banished  from  milder  regions,  these  inhospitable  Arctic  lands 
will  long  remain  in  their  wild  luxuriance  of  summer  beauty, 
where  those  who  trulv  love  nature  wdll  be  able  to  witness  one 
of  the  most  wonderful  illustrations  of  the  mvriad  forms  and 
complex  ada23tations  which  the  world  of  life  presents  to  us. 

It  is  a  significant  feature  of  this  adaptation,  that  of  all 
the  higgler  forms  of  life  birds  are  the  most  completely  pro- 
tected  from   the   blood-sucking   and    iiTitation    of   mosquitoes. 


CASES  OF  ADAPTATIO]S[ 


159 


Every  imrt  of  the  body  is  protected  either  with  a  dense  mass 
of  phimage,  or  by  a  homy  integument  on  the  bill  and  feet, 
so  that  they  are  probably  quite  undisturbed  while  enjoying 
the  super-abundant  feast  nature  has  spread  for  them  in  those 
remote  and  usually  repellent  lands.  We  may  conclude,  there- 
fore,  that   it   is   to  the   two  special   features   of  these   Arctic 


Fig.  21.— The  Higher  Tundra. 
Stanavialachta  at  mouth  of  the  Petchora  River  (N.  Lat.  69°), 

tundras  —  their  abundant  berries  preserved  during  the  winter 
in  a  natural  ice-house,  and  the  myriad  clouds  of  mosquitoes 
and  their  larvge  —  that  we  owe  the  very  existence  of  a  consid- 
erable proportion  of  the  bird-life  in  the  northern  hemisphere. 


The   Origin  of  Bird-migration 

These  vast  Arctic  plains  even  in  Tertiary  times  when 
climates  were  milder,  would,  owing  to  the  long  winter  nights, 
have  always  been  snow-covered  during  several  months  in  winter 
although  its  melting  might  have  been  earlier  and  the  sunnner 
somewhat  longer ;  there  can  be  little  doubt  that  the  short  sum- 


160  THE  WORLD  OF  LIFE 

mer  with  its  perpetual  sunshine  was  equally  favourable  to  the 
production  of  a  super-abundance  of  vegetable  and  insect  food 
very  similar  to  what  now  exists  there,  and  in  this  fact,  we 
find  a  very  complete  explanation  of  how  bird-migration  came 
about.  Abundance  of  food  suitable  for  both  parents  and 
young  at  the  season  of  breeding,  would  inevitably  attract  birds 
of  all  kinds  from  more  southern  lands,  especially  as  the  whole 
area  would  necessarily  have  no  permanent  residents  or  very 
few,  but  would,  each  recurring  season,  be  an  altogether  new 
and  unoccupied  but  most  fertile  country,  to  be  reached,  from 
any  part  of  the  north  temperate  lands,  by  merely  following 
up  the  melting  snow.  And  as,  a  few  months  later,  the  myriads 
of  young  birds  in  addition  to  their  parents  were  driven  south 
by  the  oncoming  of  the  cold  and  darkness,  they  would  find 
it  necessary  to  travel  farther  and  farther  southward,  and  would 
again  find  their  way  north  when  the  proper  season  arrived. 
There  would  always  be  a  considerable  niunber  of  the  old  and 
experienced  birds  to  show  the  way;  and  as,  with  increasing 
severity  of  the  seasons,  the  area  of  the  snow-covered  plains 
would  extend,  and  their  capacity  for  feeding  both  old  and 
young  would  be  increased ;  there  would  at  last  be  brought  about 
that  marv^ellous  rush  of  the  migrating  flocks  which  Mr. 
Seebohm  has  so  vividly  described. 

Before  quitting  the  subject  of  migration,  on  which  Mr. 
Seebohm's  observations  throw  so  much  light,  I  will  shortly 
describe  the  most  wonderful  exhibition  of  migration-phenom- 
ena in  the  world  —  that  of  the  small  island  of  Heligoland, 
40  miles  off  the  mouth  of  the  Elbe  in  about  the  same  lati- 
tude as  Scarborough.  Most  of  the  migratory  birds  from 
Scandinavia  and  xlrtic  Europe  pass  along  the  coasts  of  the 
German  Ocean,  and  the  lighthouse  on  Heligoland  serves  as 
a  guide,  and  the  island  itself  as  a  resting-place  during  bad 
weather.  Mr.  Seebohm's  account  of  what  he  witnessed  in 
the  island,  during  nearly  a  month  spent  there  in  September 
to  October  1875  (in  chapter  xx.  of  his  Siberia  in  Euroj)e) 
is   most   interesting;    and   I   refer   to   it   here   chiefly   for   the 


OASES  OF  ADAPTATION  161 

sake  of  iDointing  out  a  very  important  error  as  to  the  cause 
of  a  very  singular  fact  recorded  there,  by  Herr  Gatke,  who 
for  fifty  years,  observed  and  registered  the  migrations  both 
in  spring  and  autumn,  with  great  accuracy,  and  formed  a 
collection  of  birds  there,  perhaps  more  extensive  than  could 
be  made  at  any  other  station  in  Europe.  The  fact  observed 
was,  that,  during  the  autumn  migration,  as  regards  many 
of  the  most  abundant  species,  the  young  birds  of  the  year, 
that  is,  those  that  had  been  hatched  in  the  far  north  in  the 
preceding  June  or  July,  and  who  w^ere,  therefore,  only  about 
three  or  four  months  old,  arrived  in  Heligoland  earliest  and 
alone,  the  parent  birds  appearing  a  week  or  two  later.  This 
is  the  fact.  It  has  been  observed  on  Heligoland  for  half  a 
century;  every  resident  on  the  island  knows  it,  and  ]\Ir. 
Seebohm  declares  that  there  can  be  no  doubt  whatever  about 
it.  The  inference  from  this  fact  (dravni  by  Herr  Gatke  and 
all  the  Heligolanders,  and  apparently  accepted  by  almost  all 
European  ornithologists)  is,  that  these  young  birds  start  on 
their  migration  alone,  and  before  their  parents,  and  this  not 
rarely  or  accidentally  but  every  year  —  and  they  believe  also 
that  this  is  a  fact,  one  of  the  most  mysterious  of  the  facts 
of  migration.  Neither  Mr.  Seebohm  nor  Professor  Lloyd 
Morgan  (in  his  Habit  and  Instinct)  express  any  doubts  about 
the  inference  any  more  than  about  the  fact.  Yet  the  two 
things  are  totally  distinct ;  and  while  I  also  admit  the  fact 
observed,  I  totally  reject  the  inference  (assumed  to  be  also 
a  fact)  as  being  absolutely  without  any  direct  evidence  sup- 
porting it.  I  do  not  think  any  English  observer  has  stated 
that  the  young  of  our  summer  migrants  all  gather  together 
in  autumn  and  leave  the  country  before  the  old  birds ;  the 
American  observers  state  that  their  migrating  birds  do  not 
do  so;  while  many  facts  observed  at  Heligoland  show  that 
no  such  inference  is  required  to  explain  the  admitted  fact. 
Let  us  see  what  these  additional  facts  are. 

The    enormous    rushes    of    mic^ratorv    birds    which    rest    at 
Heligoland  always  occur  at  night,  and  are  very  intermittent. 


162 


THE  WORLD  OF  LIFE 


They  usuallj  take  place  on  dark  nights,  sometimes  in  mil- 
lions; at  other  times,  a  week  will  sometimes  pass  with  only 
a  few  stragglers.     Of  one  such  pitch-dark  night  Mr.  Seebohm 


writes : 


Fig.  22.—  The  Light- 
house at  Heligoland  on  a 
Migration  Night. 


"  Arrived  at  the  lighthouse,  an  intensely  interesting  scene  pre- 
sented itself.  The  whole  of  the  zone  of  light  within  range  of  the 
mirrors  was  alive  with  the  birds  coming  and  going.  Nothing  else 
was  visible  in  the  darkness  of  the  night,  but  the  lanthorn  of  the 
lighthouse  vignetted  in  a  drifting  sea  of  birds.  From  the  darkness 
in  the  east,  clouds  of  birds  were  continually  emerging  in  an  unin- 
terrupted stream ;  a  few  swerved  from  their  course,  fluttered  for  a 
moment  as  if  dazzled  by  the  light,  and  then  gradually  vanished 
with  the  rest  in  the  western  gloom.  ...  I  should  be  afraid  to 
hazard  a  guess  as  to  the  hundreds  of  thousands  that  must  have 
passed  in  a  couple  of  hours ;  but  the  stray  birds  that  the  lighthouse- 
man  succeeded  in  capturing  amounted  to  nearly  300." 

He  also  tells  us  that  15,000  sky-larks  have  been  caught 
on   Helifi^oland    in   one   nio-ht ;    and    all    aiiTee   that   the   count- 


CASES  OF  ADAPTATIOjST  163 

less  myriads  that  are  seen  passing  over  Heligoland  are  but 
a  minute  fraction  of  those  that  really  pass,  high  up  and  quite 
out  of  sight.  This  is  shown  by  the  fact,  that  if,  on  a  dark 
night,  it  suddenly  clears  and  the  moon  comes  out,  the  swarms 
of  birds  immediately  cease.  Another  fact  is,  that,  on  what 
the  islanders  call  ''  good  nights,'^  the  birds  that  come  to  rest 
seem  to  drop  down  suddenly  out  of  the  sky.  One  other  fact 
is  mentioned  by  Mr.  Seebohm.  It  is  that  every  year  the  reg- 
ular migration  season  is  preceded  by  a  week  or  two,  during 
which  a  few  stragglers  appear ;  and  these  are  all  old  birds 
and  many  of  them  slightly  crippled,  or  partially  moulted,  or 
without  some  of  their  toes,  or  onlv  half  a  tail,  or  some  other 
defect.  These  are  supposed  to  be  mostly  unmated  birds  or 
those  whose  young  have  been  destroyed.  It  is  also  supposed 
that,  during  favourable  weather  (for  the  birds)  migration  goes 
on  continuously  during  the  season  of  about  six  weeks,  though 
for  the  most  part  invisible  at  Heligoland,  but  often  audible 
when  quite  invisible. 

Xow,  the  fact  of  the  young  birds  only  appearing  on  Heligo- 
land for  the  first  week  or  so  of  the  season  of  each  species  is 
easily  explicable.  Rem.embering  that  the  autumnal  migration 
includes  most  of  the  parent  birds  and  such  of  their  broods  as 
have  sur^dved,  it  is  probable  that  the  latter  will  form  at  least 
half  or,  more  often,  two-thirds  of  each  migrating  flock.  But 
the  young  birds,  not  having  yet  acquired  the  full  strength 
of  the  adults,  and  having  had  little,  if  any  experience,  in 
long  and  continuous  flights,  a  considerable  proportion  of  them 
on  the  occasion  of  their  first  long  flight  over  the  sea,  on  see- 
ing the  lighthouse  and  knowing  already  that  lights  imply  land 
and  food-crops  below  them,  and  being  also  much  fatigued,  will 
simply  drop  down  to  rest  just  as  they  are  described  as  do- 
ing. The  old  birds  and  the  stronger  young  ones,  however, 
pass  high  over  head,  till  they  reach  the  north  coast  of  Hol- 
land, or,  in  some  cases,  pass  over  to  our  eastern  coasts.  We 
must  also  remember  that  the  loncrer  the  birds  are  in  mak- 
ing  the  journey  overland,  the  more  young  birds  are  lost  by 


164  THE  WORLD  OF  LIFE 

the  attacks  of  birds-of-prey  and  other  enemies.  Hence  the 
earliest  flocks  will  have  a  larger  proportion  of  young  birds  than 
the  later  ones.  The  earlier  flocks  also,  being  less  pressed  for 
time  will  be  able  to  choose  fine  weather  for  the  crossing,  and 
thus  it  will  be  only  the  young  and  quickly-fatigued  birds  that 
will  probably  fly  low  and  come  dow^n  to  rest.  Later  on  every 
recurrence  of  bad  weather  will  drive  down  old  and  young  alike 
for  temporary  shelter  and  rest.  Thus  all  the  facts  are  ex- 
plained without  having  recourse  to  the  wildly  improbable 
hypothesis  of  flocks  of  immature  birds  migrating  over  land 
and  sea  quite  alone,  and  a  week  in  advance  of  their  parents 
or  guides. 

What  this  World-wide  Adaptation  teaches  us 

This  co-adaptation  of  two  of  the  highest  and  most  marvel- 
lous developments  of  the  vast  world  of  life  —  birds  and  in- 
sects —  an  adaptation  which  in  various  forms  pervades  all 
their  manifestations  upon  the  earth,  from  the  snow^-wastes  of 
the  tundra  to  the  glorious  equatorial  forests;  and  the  further 
co-adaptation  of  both,  with  the  vegetation  amid  w'hich  they 
have   developed,   suggest   some  very  important   considerations. 

As  we  might  expect,  both  birds  and  insects  are  comparatively 
rare  in  a  fossil  state,  but  there  are  suflicient  indications  that 
the  latter  were  first  developed.  A  considerable  number  have 
been  found  in  the  Coal  Measures,  especially  numerous  cock- 
roaches. Ancestral  forms  of  ^N^europtera  and  Hemiptera  allied 
to  our  may-flies  and  dragon-flies,  bugs  and  aphides,  are  found 
in  Devonian  and  Carboniferous  rocks.  The  more  his^hlv 
organised  insects  with  a  complete  metamorphosis,  come  later; 
beetles,  dragon-flies,  and  bugs  (Hemiptera)  are  rather  common 
in  Lias  beds,  and  here,  for  the  first  time,  we  meet  with  a 
true  ancestral  bird  with  perfectly  developed  wings  and 
feathers,  and  with  toothed  jaw^s,  the  celebrated  Archseopteryx. 
Diptera  (flies)  are  also  found  here,  as  ^vell  as  a  wasp,  some- 
what doubtfully  identified ;  while  the  most  highly  developed 
of  all  insects  in  structure  and  metamorphosis,   as   well   as  in 


CASES  OF  ADAPTATION"  16^ 


o 


size  and  beauty,  the  Lepidoptera,  are  first  in  Tertiary  beds, 
at  a  time  when  birds  allied  to  living  forms  also  first  appeared. 
This  general  parallelism  of  development  seems  clearly  to 
indicate  that  birds,  in  the  full  and  varied  perfection  in  which 
we  now  find  them,  are  dependent  on  a  correspondingly  wide- 
spread development  of  insects ;  and  more  especially  of  those 
higher  orders  of  insects,  whose  exceedingly  diverse  stages  of 
larva,  pupa,  and  perfect  insect,  afforded  the  special  food  for 
immature  and  full-grown  birds  respectively.  We  can  see  how 
the  omnipresence  of  insects  adapted  to  feed  on  every  kind  of 
vegetable  food,  as  well  as  on  all  kinds  of  animal  refuse,  has 
afforded  sustenance  to  the  various  kinds  of  small  mammalia, 
reptiles,  and  birds,  which  have  successively  become  specialised 
to  capture  and  feed  on  them.  The  early  birds  with  toothed 
jaws  were  able  to  feed  upon  the  cockroaches  and  ancestral 
iVTeuroptera  and  beetles  of  the  same  period.  As  these  early, 
birds  became  more  numerous,  so  they  became  successively 
specialised  to  feed  upon  particular  kinds  of  insects  or  their 
larvae,  however  completely  these  might  seem  to  be  concealed 
or  protected.  Thus  were  gradually  formed  the  true  fly- 
catchers (Muscicapidge)  and  the  totally  distinct  American  fly- 
catchers or  tyrant  birds  (Tyrannidse),  which  capture  all  kinds 
of  insects  on  the  wing;  the  swallows,  and  the  very  distinct 
swifts,  so  specialised  as  almost  to  live  in  the  air,  and  to  feed 
on  this  kind  of  food  exclusively;  the  goatsuckers,  which 
capture  night-flying  insects;  the  curious  little  nuthatches  and 
creepers  which  hunt  over  trees  for  small  beetles  concealed  in 
crevices  of  the  bark;  while  the  marvellously  specialised  wood- 
peckers discover  the  larger  grubs  or  caterpillars  which  burrow 
deeply  into  the  wood  of  trees,  and  dig  down  to  them  with 
their  wonderfully  constructed  hammer-and-chisel-like  head 
and  bill,  and  then  pull  them  out  on  the  tip  of  their  extensile 
barbed  tongue.  In  the  tropics  many  distinct  families  of  birds 
have  been  developed  to  grapple  with  the  larger  and  more 
varied  insect  forms  of  those  countries,  so  that  it  mav  be 
safely  concluded  that  no  group  of  the  vast  assemblage  of  in- 


166  THE  WORLD  OF  LIFE 

sects  but  what  has  its  more  or  less  dangerous  enemies  among 
the  birds.  Even  the  great  rapacious  birds,  the  hawks,  buz- 
zards, and  owls,  when  their  special  food,  the  smaller  mammals 
and  birds,  fails  them,  will  capture  almost  every  kind  of 
ground-feeding  insects;  while  the  enormous  tribes  which  feed 
largely  on  frnits  and  seeds  often  make  up  for  its  deficiency 
by  capturing  such  insects  as  are  available. 

One  of  the  clearest  deductions  from  these  facts  is,  that  the 
great  variety  of  the  smaller  birds  —  warblers,  stonechats,  tits, 
w^agtails,  pipits,  wrens,  and  larks  —  owes  its  origin  to  the 
continuous  specialisation  throughout  the  ages  of  new  forms  of 
birds  adapted  to  take  advantage  of  every  fresh  development 
of  the  insect  tribes  as  they  successively  came  into  existence. 
As  Darwin  repeatedly  impresses  upon  us,  excessive  powers  of 
multiplication  with  ever-present  variations,  lead  to  the  almost 
instant  occupation  of  every  vacant  place  in  the  economy  of 
nature,  by  some  creature  best  fitted  to  take  advantage  of  it. 
Every  slight  difference  in  the  shape  or  size  of  bill,  feet,  toes, 
wing,  or  tail,  or  of  colour  of  the  various  parts,  or  of  supe- 
rior acuteness  in  anv  of  the  senses,  such  as  we  can  see  in  the 
different  allied  species  of  these  birds,  has  been  sufficient  to 
secure  the  possession  of  some  one  of  these  vacant  places ;  and 
when  this  first  partial  adaptation  has  been  rendered  more  and 
more  perfect  by  the  survival  in  each  successive  generation  of 
those  individuals  best  fitted  for  the  exact  conditions  of  the 
new  environment,  a  position  is  reached  which  becomes  at  any 
future  time  a  secure  starting-point  for  further  modification, 
either  in  the  same  or  in  any  slightly  diverging  line,  so  as  to 
be  again  fitted  to  occupy  some  other  vacant  place  which  may 
have  arisen  through  the  slightest  changes  either  in  the  inor- 
ganic or  the  organic  environment. 

So  long  as  we  limit  ourselves  to  a  consideration  of  the  mode 
in  which  any  existing  species  has  been  produced,  by  the 
adaptive  modification  of  some  other  pre-existing  closely  allied 
species,  by  means  of  the  known  facts  of  universal  variation 
and  of  the  constant  survival  of  the  best  adapted,  there  is  no 


CASES  OF  ADAPTATION  167 

difficulty  whatever  in  accepting  the  "  origin  of  species  "  from 
other  species  as  a  demonstrated  fact ;  and  this  alone  was  the 
hitherto  insoluble  problem  Avhich  Darwin  first  succeeded  in 
solving.  It  is  only  in  the  extension  of  the  process  to  isolated 
groups  such  as  the  whales,  the  elephants,  the  serpents,  or  the 
mammalia;  or  by  enquiring  how  special  organs,  such  as  horns, 
teeth,  ears,  or  eyes,  could  have  begun  their  process  of  develop- 
ment, that  difficulties  appear,  many  of  which  seem,  to  some 
biologists,  to  be  insuperable.  But  many  of  these  difficult 
problems  have  been  solved  by  more  complete  knowledge ;  while 
others  have  been  rendered  easy  by  the  discovery  of  inter- 
mediate stages  either  through  the  investigations  of  embryolo- 
gists,  or  of  palaeontologists,  so  that  many  of  the  greatest  diffi- 
culties of  Darwin's  early  opponents  have  quite  disappeared. 
Some  of  these  recent  explanations  have  been  referred  to  al- 
ready, and  many  others  are  briefly  described  in  my  Darwin- 
ism. In  that  work  also  I  have  given  so  many  illustrations 
of  the  way  in  which  natural  selection  has  worked,  that  it  will 
be  needless  for  me  to  go  into  further  details  here.  I  will, 
therefore,  now  proceed  to  an  exposition  of  some  problems  of 
a  more  general  nature,  which  involve  difficulties  and  sugges- 
tions beyond  the  scope  of  Dar^vin's  work,  and  which,  I  think, 
have  not  been  sufficiently  considered  by  later  writers  on  evolu- 
tion. 


CHAPTER  IX 

THE   IMPORTANCE    OF   EECOGNITION-MAKKS   FOR  EVOLUTION 

The  great  problem  of  the  exact  causes  of  the  infinitely  varied 
colours  and  markings  of  the  different  species  of  the  higher 
animals,  is  now  gradually  receiving  an  adequate  amount  of 
attention,  and  in  consequence  an  almost  complete  solution. 
In  the  Origin  of  Species  Darwin  dealt  with  only  one  branch, 
of  the  subject  —  coloration  for  concealment,  and  that  only  in- 
cidentally ;  but  he  at  once  accepted,  and  with  enthusiasm, 
Bates's  explanation  of  the  beautiful  phenomena  of  mimicry 
among  insects,  and  also  that  of  warning  colours  in  the  in- 
edible caterpillars,  first  suggested  by  myself. 

The  whole  subject,  especially  that  of  mimicry,  is  now  so 
largely  developed  as  to  require  many  volumes  for  its  adequate 
exposition ;  and  I  have  myself  given  a  summary  of  the  more 
interesting  facts  in  my  Darwinism:  I  shall  therefore  deal  very 
briefly  with  it  here,  with  the  one  exception  of  that  form  of 
it  which  I  have  named  "  recognition  marks."  These,  though 
the  last  to  be  generally  accepted  have  received  the  least  at- 
.  tent  ion ;  but,  after  many  years'  consideration  of  the  whole 
problem  of  evolution  I  have  come  to  the  conclusion  that,  of 
all  the  causes  of  distinctive  marking  (among  the  higher  ani- 
mals at  all  events),  the  need  for  easy  recognition  under  the 
varied  conditions  of  their  existence  is  for  most  animals  the 
most  important.  It  is,  however,  on  account  of  their  being 
in  most  cases  absolutely  essential  as  a  factor  in  the  evolution 
of  new  species  that  I  here  devote  the  larger  part  of  this  chapter 
to  their  consideration. 

168 


KECOGA^ITIO^^ -MARKS  169 

Coloration  for  Concealment  and  for  Visibility 

Colour  and  markings  for  concealment  pervade  all  nature. 
The  hare  on  its  form,  the  snipe  in  its  covert,  the  vast  major- 
ity of  birds  while  sitting  on  their  nests,  the  sand-coloured  des- 
ert animals,  and  the  prevalence  of  green  colours  in  the  in- 
habitants of  tropical  forests,  are  a  few  of  the  best-known  ex- 
amples. The  uses  of  such  colours  in  order  to  protect  the 
Herbivora  from  enemies,  or  to  conceal  those  which  devour 
other  animals  from  their  prey  was  at  once  acknowledged,  and 
it  was  seen  how,  with  variability  of  colour  as  a  constant  fact, 
survival  of  the  fittest  might  soon  bring  about  the  beautiful 
harmony  of  coloration  we  everywhere  find  to  prevail.  But  it 
was  also  undeniable  that  there  were  almost  equal  numbers 
of  animals  of  all  classes  and  sizes,  in  which  colours  and  mark- 
ings occurred  which  could  not  by  any  possibility  be  interpreted 
as  protective,  because  they  seemed  to  render  the  creature 
glaringly  conspicuous.  Some  of  these,  which  w^ere  most  prev- 
alent among  insects,  were  soon  explained  as  "  warning 
colours,' '  because  they  were  exhibited  by  species  which  were 
either  so  nauseous  as  to  be  inedible  by  most  insect-eaters ;  or 
were  armed  wdth  stings  which  might  cause  great  pain  or  even 
loss  of  life  to  an  enemy  which  attacked  them.  When  it  was 
found  that  many  other  groups  of  insects  which  did  not  pos- 
sess these  protective  qualities,  yet  acquired  the  same  colours 
and  often  the  same  form ;  and  when  my  fellow-traveller  on 
the  Amazon,  II.  W.  Bates,  showed  how  this  peculiar  kind  of 
^^  mimicry "  was  beautifully  explained  on  the  Danvinian 
hypothesis,  not  only  w^as  the  theory  itself  greatly  strengthened 
but  a  whole  host  of  curious  and  beautiful  colour-phenomena 
in  Xature,  hitherto  unnoticed,  were  seen  to  come  under  some 
form  of  the  same  general  principle.  As  one  rather  extreme  ex- 
ample of  mimicry  I  give  the  figures  of  a  black  wasp  with  white- 
banded  wings,  which  is  closely  imitated  by  a  heteromcrous 
beetle.  These  I  captured  myself  in  the  forests  of  Borneo,  fly- 
ing together  near  the  ground.     They  are  of  nearly  the  same 


170  THE  WOKLD  OF  LIFE 

size.  The  wing-coverts  (elytra)  of  the  beetle  are  reduced  to 
pointed  scales,  allowing  the  true  wings  to  be  always  extended. 
This  is  most  unusual  in  beetles,  as  is  the  white  band  across 
the  wings  in  this  order  of  insects  (Fig.  23).  This  strange 
and  most  unusual  modification  of  an  inoffensive  insect,  so 
as  closely  to  resemble  one  of  another  order  which  is  protected 
by  a  dangerous  sting,  can  be  explained  in  no  other  way  than 
through  the  advantage  derived  by  the  harmless  beetle  by  be- 
ing mistaken  for  the  wasp.  Of  course,  this  change  is  the 
result  of  a  very  long  series  of  slight  modifications  of  the  beetle, 
each  bringing  it  a  little  nearer  to  the  wasp,  a  series  extend- 
ing probably  through  thousands  or  even  millions  of  genera- 
tions.^ 

Becogniiion-Marlcs 

But  though  the  subject  of  '^  mimicry "  involves  problems 
of  extreme  complexity  and  interest,  and  has  therefore  at- 
tracted the  attention  of  numerous  students,  yet  it  is  almost 
entirely  confined  to  the  insect  world,  and,  taken  as  a  whole, 
is  not  nearly  so  important  a  factor  in  the  development  of  the 
great  Avorld  of  life  as  the  class  of  "  recognition  "-colours  of 
which  I  will  now  give  a  short  account. 

My  attention  was  first  directed  to  this  subject  during  my 
visit  to  south  Celebes  in  1856-57,  where,  during  about  six 
months'  collecting,  I  obtained  the  unusual  number  of  fifteen 
different  birds  of  prey,  of  which  the  majority  were  of  the 
hawk  sub-family.  While  skinning  and  preserving  these  birds, 
and  after  my  return  home,  wdiile  determining  the  species,  I 
could   not  help   observing  in   many   of   them   the  varied   and 

1  Other  cases  are  given  in  my  Darwinism ;  but  those  who  wish  to  under- 
stand the  whole  problem  and  what  an  important  part  it  plays  in  nature 
should  read  Professor  Poulton's  elaborate  papers  in  the  Transactions  of 
the  Entomological  Society  of  London  for  the  years  1902  and  1908,  together 
with  those  of  Dr.  F.  A.  Dixey  and  other  writers.  There  is  also  a  very  good 
article  by  Mr.  E,.  Shelford,  on  mimetic  insects  from  Borneo,  and  as  these 
are  illusttated  by  coloured  plates  and  deal  with  cases  of  the  same  nature  as 
the  one  here  given,  they  are  very  instructive.  (See  Proceedings  of  the 
Zoological  Society  of  London,  Nov.  4,  1902.) 


beetle. 


i.MYCNIMIA  AVICULUS. 
2.C0L0B0RH0MBUS  FASCIATIPENNIS, 


Fig.  23. —  Mimicry  of  Wasp  by  a  Beetle. 


EECOGNITION-MAEKS  171 

beautiful  markings  of  the  tail-feathers,  by  means  of  white 
spots  or  bands  on  all  the  feathers  except  the  middle  pair. 
The  result  was  that  when  the  tail  was  expanded  during 
flight,  it  was  seen  to  be  marked  very  conspicuously  by  white 
bands,  sometimes  across  the  middle  of  the  tail,  sometimes  at 
the  end,  sometimes  with  one  band,  sometimes  with  two  or  even 
three,  so  that  the  species  were  easily  distinguished  by  this  one 
character.  But  the  chief  peculiarity  to  be  noticed  was,  that 
these  bands  w^ere  only  seen  during  flight,  the  white  markings 
being  quite  invisible  when  the  birds  were  at  rest.  The  impor- 
tance of  this  fact  I  did  not  see  till  many  years  later,  when, 
in  connection  with  other  similar  facts,  it  gave  a  clue  to  their 
meaning  and  purpose. 

Xow  that  we  have  learnt  how  rapid  are  the  powers  of  in- 
crease of  all  animals,  and  the  extreme  severity  of  the  process 
by  which  the  population  is  kept  down  to  a  nearly  fixed  amount 
by  the  annual  destruction  of  all  the  less  adapted ;  and  further, 
when  we  know  how  all  the  higher  animals  roam  about  in 
search  of  their  daily  food,  we  are  able  to  understand  how 
vitally  important  it  is  for  all  such  animals  to  be  able  to  recog- 
nise their  own  species  from  all  others  without  fail  and  at  con- 
siderable distances.  This  is  essential  for  several  reasons. 
The  young  and  half-grown,  if  they  have  strayed  away  from 
the  flock  or  herd,  need  to  rejoin  them  as  soon  as  possible ;  the 
two  sexes  of  the  same  species  require  to  know  each  other  in 
the  same  way  by  unfailing  marks  whether  they  are  approach- 
ing from  behind  or  from  the  front;  while  the  separate  por- 
tions of  flocks  divided  by  the  sudden  attack  of  some  enemy 
need  to  come  together  again  as  soon  as  possible.  But  there  is 
a  still  more  important  use  of  these  distinctive  markings,  since 
they  are  almost  if  not  quite  essential  to  the  production  of  neiv 
species  by  adaptation  to  change  of  conditions,  as  will  be  shown 
later  on. 

I  first  gave  a  somewhat  full  account  of  this  class  of  mark- 
ings, with  several  characteristic  illustrations,  in  my  Darwin- 
ism, in  1889;  but  I  had  briefly  treated  the  subject   in  my 


172r  THE  WOELD  OF  LIFE 

lecture  on  the  Colours  of  Animals  given  at  many  places  in 
the  United  States  and  Canada  in  1886-87,  and  in  England  in 
1888.  No  doubt  some  of  the  facts  had  been  noted  by  other 
writers,  but  I  thinlv  I  was  the  first  to  claim  for  it  a  high  place 
among  the  factors  concerned  in  animal  evolution.  The  clear- 
est and  most  picturesque  illustration  of  the  subject  1  have  seen 
is  in  a  very  short  article  by  Mr.  E.  Seton  Thompson  in  the 
American  periodical  "  The  Auk "  for  October  1897,  from 
which  I  will  quote  the  most  important  passage : 

"  The  common  jack-rabbit  ^  when  squatting  under  a  sage-bush 
is  simply  a  sage-gray  lump  without  distinctive  colour  or  form.  Its 
colour  in  particular  is  wholly  protective,  and  it  is  usually  accident 
rather  than  sharpness  of  vision  which  betrays  the  creature  as  it 
squats.  But  the  moment  it  springs  it  is  wholly  changed.  It  is 
diflScult  to  realise  that  this  is  the  same  animal.  It  bounds  away 
with  erect  ears  showing  the  black  and  white  markings  on  their  back 
and  underside.  The  black  nape  is  exposed.  The  tail  is  carried 
straight  down,  exposing  its  black  upper  part  surrounded  by  a  region 
of  snowy  white ;  its  legs  and  belly  show  clear  white,  and  everything 
that  sees  it  is  clearly  notified  that  this  is  a  jach-rabhit.  The  coyote, 
the  fox,  the  wolf,  the  badger,  etc.,  realise  that  it  is  useless  to  follow ; 
the  cotton-tail,  the  jumping  rat,  the  fawn,  the  prairie  dog,  etc.,  that 
it  is  needless  to  flee;  the  young  jack-rabbit  that  this  is  its  near 
relative,  and  the  next  jack-rabbit  that  this  may  be  its  mate.  And 
thus,  though  incidentally  useful  to  other  species  at  times,  the  sum 
total  of  all  this  clear  labelling  is  vastly  serviceable  to  the  jack-rab- 
bit, and  saves  it  much  pains  to  escape  from  real  or  imaginary 
dangers.  As  soon  as  it  squats  again  all  the  directive  marks  disap- 
pear, and  the  protective  gray  alone  is  seen.  In  the  bird-world  the 
same  general  rule  applies.  When  sitting,  birds  are  protectively 
coloured;  when  flying,  directivelyf  i 

The  African  antelopes  offer  very  striking  examples  of 
"  recognition  "-marks,  especially  those  that  inhabit  Central  and 
South  Africa,  where  such  indications  are  most  needed.  The 
land  is  generally  open,  often  quite  bare,  but  usually  with  scat- 

1  This  appears  to  be  the  common  grey  hare  {Lepiis  a^nericanus) . 


KECOGNITION-MAEKS  173 

tered  trees   and  bushes ;   and   as  these  animals   roam   over  a 
great  extent  of  country  in  search  of  food  or  water,   and  are 
also  liable  to  the  attacks  of  many  dangerous  beasts  of  prey, 
their  safety  depends  largely  on  their  keeping  together  in  small 
or  large  herds.     There  are  nearly  a  hundred  different  kinds 
of  antelopes  known  to  inhabit  Africa,  the  larger  part  of  them 
being  found  in  Central  and  South  Africa.     Almost  all  of  these 
have   very    distinctive    markings    on    a   general   ground-colour 
harmonising  with  the  tint  of  the  soil  or  rock.     These  mark- 
ings are  usually  confined  to  white  patches  on  the  head  and 
face,  and  on  the  hinder  parts,  so  as  to  be  visible  in  the  two 
directions   that   are  most   serviceable.-^     I   have   also   come   to 
the   conclusion  that  the  horns  of  these   animals,  though   pri- 
marily developed  as  weapons  of  defence  —  for  even  the  lion 
is  occasionally  killed  by  the  horns  of  the  gemsbuck  —  have 
been  so  changed  in  each  species  as  to  serve  another  purpose, 
as  is   so  often  the   case   in  nature.     Their  curious   modifica- 
tions   of   form    in   closely    allied    species,    and    their    extreme 
diversity  in  the  whole  group,  leads  me  to  conclude  that  their 
actual  shapes  have  been  produced  quite  as  much  for  purposes 
of  recognition  as  for  attack  or  defence.     While  moving  among 
high  grass  or  bushes,  or  when  at  rest  and  '^  ruminating,"  the 
horns  would  often  be  the  only  part  visible  at  a  distance ;  and 
this,  in  a  district  inhabited  by  perhaps  a  dozen  different  species 
of  these  animals,  would  be  of  the  greatest  importance  in  guid- 
ing a  wanderer  back  to  his  own  herd,  and  for  other  purposes. 
To  illustrate  this  I  here  give  views  of  the  horns  or  heads  of 
twelve  different  species  of  antelopes  all  found  in   Central  or 
South  Africa,  and  thus  often  meeting  in  the  same  valley  or 
veldt.     To  these  I  call  the  reader's  special  attention  (Figs.  24- 
35). 

The  first  group  of  four  shows  two  of  the  larger  antelopes 

1  The  beautiful  gazelle  figured  in  my  Darwinism  (p.  219)  shows  both 
these  kinds  of  markings  very  strongly;  while  an  examination  of  the  numer- 
ous figures  of  antelopes  in  Wood's  Natural  History  (or  in  any  of  the  more 
recent  illustrated  works)   aff'ords  numerous  examples  of  them. 


174  THE  WORLD  OF  LIFE 

on  the  left,  which,  with  a  general  likeness  of  form,  possess 
individuality  both  in  face-marks  and  in  the  curvature  of  the 
horns ;  while  the  two  gazelles  on  the  right  are  still  more 
distinct.  The  next  group  consists  of  three  species  of  the 
genus  Cobus,  in  w^hich  the  horns  are  each  so  distinct  in  size 
and  curvature  as  to  be  easily  recognisable  at  considerable  dis- 
tances ;  the  fourth  figure  shows  the  horns  of  the  gemsbuck,  a 
very  distinct  species,  not  only  in  the  body  markings,  but  also 
in  the  almost  perfectly  straight  and  very  long  horns.  The 
third  group  shows,  at  the  top,  the  two  species  of  kudu,  the 
horns  of  which,  though  exactly  alike  in  spiral  curvature,  are 
yet  placed  at  such  a  different  angle  on  the  head  as  to  be  easily 
distinguishable.  The  two  lower  figures  are  of  animals  not 
closely  allied,  but,  as  one  inhabits  East  and  the  other  South 
Africa,  their  ranges  probably  overlap  each  other,  or  once  did 
so.  Here  there  is  a  somewhat  similar  bend  in  the  horns,  but 
their  thickness  and  direction  render  them  absolutely  distinct 
from  every  point  of  view. 

^Now,  as  the  antelopes  are  very  closely  allied  to  each  other, 
both  in  structure  and  external  form,  it  seems  improbable  that 
all  the  diversities  in  the  horns  (which  are  sometimes  very 
great  in  closely  allied  species)  should  have  been  acquired  for 
the  sole  purpose  of  fighting  with  each  other  or  with  an  enemy. 
But  as  these  animals  all  possess  markings  on  the  head  and 
body  which  can  only  be  interpreted  as  recognition-marks  es- 
pecially serviceable  while  in  motion,  it  seems  quite  natural  that 
the  horns  should  have  been  modified  to  serve  the  same  pur- 
pose while  the  animals  are  at  rest,  or  when  their  bodies  are 
wholly  and  their  faces  partially  concealed  by  the  grasses  or 
bushes  around  them. 

The  essential  character  of  directive  or  recognition-marks 
is  strikingly  shown  by  one  of  the  best  known  of  the  African 
antelopes  —  the  springbok  —  which  in  the  early  days  of  the 
Cape  Colony  swarmed  over  the  whole  of  South  Africa,  even 
in  the  vicinity  of  Cape  Town.  Its  chief  feature  is  thus  de- 
scribed in  Chambers's  Encyclopaedia : 


Fig.  24. 
TrageJayhus  spekei. 


Fig.  25. 
Boocercus   euryceros. 


Fig.  26.  Fig.  27. 

Gazella  granti.  Gazella   ualleri. 

Recognition-Marks  in  African  Antelopes. 


KECOGNITION-MAEKS  175 

"  Two  curious  folds  of  skin  ascend  from  the  root  of  the  tail  to 
near  the  middle  of  the  back;  they  are  closed  when  the  animal  is 
at  rest,  but  when  leaping  or  running  they  open  out  and  disclose  a 
large  white  patch,  which  is  otherwise  concealed." 

We  have  here  a  structural  peculiarity  leading  to  the  pro- 
duction of  a  distinctive  white  patch  on  a  prominent  part  of 
the  body,  which  patch  is  concealed  Avhen  not  required  and 
when  it  might  be  dangerous,  and  only  exhibited  in  the  pres- 
ence of  some  real  or  imaginary  danger,  for  the  sj^ringbok  is 
said  to  be  one  of  the  most  timid  and  cautious  of  all  animals. 
This  curious  feature  is  more  remarkable,  and  more  clearly  a 
proof  of  a  mark  designed  to  he  seen,  than  even  our  rabbit's 
upturned  tail  wdien  running,  wdiich  has  been  termed  the 
*^  signal  Hag  of  danger,"  and  in  moonlight  or  evening  twilight 
serves,  on  the  approach  of  an  enemy,  to  guide  the  young,  or 
those  farthest  from  home,  towards  the  family  burrow. 

Recognition-Marks  in  Birds 

A  large  number  of  birds  also  possess  these  two  kinds  of 
recognition-markings,  the  one  to  be  seen  when  resting  or  feed- 
ing, the  other  only  during  flight.  As  good  examples  of  these 
I  give  figures  of  the  head  and  wings  of  three  allied  species 
of  stone-curlews,  inhabiting  Eastern  Australia,  the  Malay 
Archipelago,  and  India,  respectively,  whose  ranges  sometimes 
overlap,  and  which  are  no  doubt  descended  from  a  common 
ancestor.  The  head  of  each  exhibits  different  markiuirs,  bv 
which  they  can  be  easily  distingTiished  while  feeding  on  the 
ground ;  while  the  bolder  markings  on  the  wings  enable  them 
to  keep  together  during  their  wanderings  or  migrations  (Figs. 
36,  37,  and  38). 

Markings  of  this  character,  though  varied  almost  infinitely, 
occur  in  all  classes  of  the  hioher  animals,  and  very  mucli 
in  proportion  as  their  mode  of  life  requires  them.  When  con- 
cealment is  of  more  importance,  then  the  recognition  is  made 
effective  by  differences  of  shape  or  of  motions  and  attitudes, 


176 


THE  WORLD  OF  LIFE 


or  hy  special  cries,  as  in  the  cuckoo.  Among  the  birds  of 
the  tropical  forests,  while  the  ground  colour  is  often  protec- 
tive, as  in  the  green  of  parrots,  the  smaller  fruit-pigeons  of 


Fig.  36. —  (Edicnemus  grallarius   (East  Australian  Stone-Curlew). 
This    species   is    found    all    over   Eastern    Australia    and    the    coasts    of    the    Gulf    of 
Carpentaria.      It   is    distinguished    from   its    allies    by    the    better   defined   whit© 
spot  on  the  wing  and  its  more  conspicuous  markings  on  the  breast. 


Fig.    37. —  (Edicnemus  magnirostris    (Austro-Malayan    Stone-Curlew). 
This   species  ranges    from   the    Andaman   Islands    to    the    Philippines    and    the   north 
coast    of    Australia.      The    markings    of    the    face    are    almost    intermediate    be- 
tween those  of  the  other  two  species. 

the  Malay  Archipelago,  many  of  the  barbets,  and  hosts  of  other 
birds,  yet  the  different  species  will  be  almost  always  charac- 


Fig.  28. 
Strepsiceros    kudu. 


FIG.  29. 
Strejisiceros   im  herb  is. 


FIG.  30. 
Buhalis   jacksoni. 


Fig.  31. 
JEpyceros    melampus. 


Recognition-Marks  in  African  Antelopes. 


RECOG^^ITION-MARKS 


>-^7 


177 


terised  bj  spots  or  bands,  or  caps  of  brilliant  or  contrasted 
colours.  But  as  these  usually  break  up  the  green  body  into 
irregular  portions,  and  as  flowers  of  equally  varied  hues  are 
common  on  trees,  or  on  the  orchids  and  other  epiphytes  that 


Fig.  38. —  (Edicnemus  recurvirostris  (Great  Indian  Stone-Curlew). 
This  species  is  found  all  over  India,   and  also  in  Ceylon  and  Burma.      This  species 
is  clearly  defined  by  the  upturned  bill  and  the  compact  black  mark  around  the 
eye. 

grow  upon  their  branches,  the  general  effect  is  by  no  means  con- 
spicuous. 

]^ow,  without  this  principle  of  the  necessity  for  external 
differences  for  purposes  of  recognition  of  each  species  by  their 
own  kind,  and  especially  of  the  sexes  by  each  other,  this  end- 
less diversity  of  colour  and  marking,  when  not  protective,  seems 
difficult  to  explain.  The  Duke  of  Argyll,  in  his  interesting 
work,  The  Reign  of  Law,  published  six  years  after  the  Origin 
of  Species,  expressed  this  objection  very  forcibly.  After  de- 
scribing many  of  the  wonderful  forms  and  ornaments  of  the 
humming-birds,  he  says : 

"  Mere  ornament  and  variety  of  form,  and  these  for  their  own 
sake,  is  the  only  principle  or  rule  with  reference  to  which  Creative 
Power  seems  to  have  worked  in  these  wonderful  and  beautiful 
birds.  ...  A  crest  of  topaz  is  no  better  in  the  struggle  for 
existence  than  a  crest  of  sapphire.     A  frill  ending  in  spangles  of 


178  THE  WORLD  OF  LIFE 

the  emerald  is  no  better  in  the  battle  of  life  than  a  frill  ending 
in  spangles  of  the  ruby.  A  tail  is  not  affected  for  the  purpose  of 
flight,  whether  its  marginal  or  its  central  feathers  are  decorated 
with  white.  .  .  .  Mere  beauty  and  mere  variety,  for  their  own 
sake,  are  objects  w^hich  we  ourselves  seek  when  we  can  make  the 
forces  of  nature  subordinate  to  the  attainment  of  them.  There 
seems  to  be  no  conceivable  reason  why  we  should  doubt  or  question 
that  these  are  ends  and  aims  also  in  the  forms  given  to  living  or- 
ganisms." 

In  a  criticism  of  the  Duke's  book  (written  in  1867)  I 
adduced  sexual  preference  by  the  female  bird  as  sufficiently 
explaining  these  varieties  of  plumage  and  colour,  but  I  have 
since  come  to  doubt  the  validity  of  this,  except  so  far  as  the 
plumes  are  an  indication  of  sexual  maturity;  while  I  see  in 
the  need  for  outward  marking,  whether  for  purposes  of  recog- 
nition or  as  preventing  intercrossing  between  incipient  species, 
a  sufficient  cause  for  all  such  conspicuous  indications  of 
specific  diversity  as  are  found  perv^ading  the  whole  vast  world 
of  life.  It  now  only  remains  to  point  out  how  these  mark- 
ings have  been  produced,  even  under  conditions  which  some 
writers  have  considered  must  render  their  production  for  this 
purpose  impossible,  and  therefore  as  constituting  a  valid  ob- 
jection to  the  whole  theory  of  recognition-marks. 

An  Objection  to  Recognition-Marhs  answered 

In  a  book  on  Darwinism  and  Lamarckism,  the  late  Captain 
Hutton,  a  well-known  Kew  Zealand  naturalist,  objected  to  the 
validity  of  recognition-marks  as  a  cause  for  the  development 
of  specific  characters,  that  there  are,  all  over  the  Pacific, 
numerous  cases  of  small  fruit-pigeons  of  the  genus  Ptilopus, 
which  each  have  distinctive  markings,  and  are  almost  always 
confined  to  one  island  or  a  small  group  of  islands.  In  most 
of  these  cases  there  is  no  other  pigeon  or  other  bird  on  the 
same  island  for  which  they  could  possibly  be  mistaken.  He 
then  says : 


^ 
fr 


^ 


Fto.  32. 

Cohiis  leche. 


Fig.  33. 

Col) us   defdssd. 


FIG.  34. 

Cohus  maria 


Fig.   35. 
Oryx  (lazclUi. 

RECOG.MTIO.N  M  \HKS    IX    Afuua.n    AXTKI.orKS. 


EECOGXITIOX-MAEKS  179 

^^  Consequently  it  appears  certain  that  most  of  these  species  were 
developed  singly,  each  in  its  own  island.  If  this  he  the  case, 
the  colours  which  now  distinguish  tlic  dilferent  species  cannot  be 
recognition-marks,  because  there  is  no  other  species  in  each  island 
with  which  they  could  be  confounded." 

Shortly  afterwards  the  late  Dr.  St.  George  Mivart  made 
the  same  objection  as  regards  the  very  numerous  species  of 
beautifully  coloured,  lories  Avhich  are  found  in  all  the  islands 
around  Xew  Guinea  and  in  the  Western  Pacific.  He  urijed 
that  the  various  peculiarities  of  colour  cannot  be  useful  as 
recognition-marks,  because  the  colour  and  markings  of  each 
of  the  2,'enera  of  these  birds  is  so  very  distinct  from  that  of 
all  other  birds  inhabiting  the  same  island,  and  there  is  usually 
only  one  species  in  each  island.  This  argument,  looked  at 
superficially,  seems  very  strong,  but  it  is  not  difficult  to  show^ 
that  it  is  a  complete  fallacy,  if  we  follow  out  in  detail  what 
must  have  occurred  in  each  case. 

It  is  clear,  admitting  evolution  (as  both  these  writers  did 
admit  it),  that  each  of  the  species  of  pigeon  or  lory  noW' 
peculiar  to  an  island  must  have  originated  from  some  parent 
species  in  the  same  or  some  other  island;  and  there  are  only 
tw^o  possible  suppositions  —  either  the  species  originated  in  is- 
land A  by  modification  of  the  present  form,  and  then  migrated 
to  island  B,  afterwards  becoming  extinct  in  A ;  or  it  migrated 
from  A  to  B  and  became  modified  into  its  present  form  in 
B.  The  latter  case  is  by  far  the  more  probable,  and  as  it  is 
clearly  that  which  the  critics  contemplated,  let  us  see  exactly 
what  must  have  happened. 

We  know  as  a  fact  that,  when  any  species  reaches  an  is- 
land or  other  new  habitat  for  the  first  time,  if  the  conditions 
are  favourable,  it  increases  with  marvellous  rapidity,  till  the 
island  is  fully  stocked,  and  the  supply  of  food  at  some  time 
of  the  year  begins  to  fail,  or  till  some  enemy  —  a  rapacious 
bird,  for  instance  —  finds  out  the  rich  banquet,  and  is  soon 
followed  by  others.  The  rabbit  in  Xew  Zealand  and  Porto 
Santo,   the   sparrow   in  the   United   States,   and   many   others, 


180  THE  WORLD  OF  LIFE 

are  examples  of  such  rapid  increase.  But  as  soon  as  the  is- 
land is  fully  stocked,  a  number  equal,  or  nearly  so,  to  the 
annual  increase  must  die  off  every  year,  and  these  will  inevi- 
tably be  the  least  fitted  to  survive.  Hence  natural  selection 
at  once  begins  to  act,  and  as  the  conditions,  even  in  two 
adjacent  islands,  are  never  quite  the  same,  and  as  with  such 
a  large  population  slight  variations  in  many  directions  will 
be  very  numerous,  some  modification  to  a  more  perfectly 
adapted  form  will  necessarily  follow.  Here  comes  the  point 
which  both  critics  failed  to  notice,  that  the  modification  of 
the  species  into  a  better-adapted  one  must  have  occurred  in 
the  island ;  and  as  it  is  universally  admitted  that  intercrossing 
between  the  incipient  species  and  the  parent  stock  would  be  a 
serious  check  to  adaptation ;  and  further,  that  varieties  of  the 
higher  animals  prefer  to  mate  with  their  like,  then  any  varia- 
tion of  colour  in  those  better  adapted  will  be  advantageous, 
will  lead  to  more  rapid  change,  and  will  thus  come  to  charac- 
terise the  new  form  as  distinguished  from  that  of  the  less- 
adapted  parental  form. 

It  is  clear,  therefore,  that  species  which  are  now  peculiar 
to  some  island  or  other  restricted  locality,  even  when  thev 
are  quite  unlike  anything  else  now  living  around  them,  must 
have  become  differentiated  from  some  parent  stock  just  in  the 
same  way  as  all  other  species  have  become  differentiated. 
During  all  the  initial  stages,  w^hich  may  have  occupied  scores 
or  hundreds  of  generations,  some  outward  sign  of  the  struc- 
tural change  that  was  taking  place  was  an  essential  part  of 
the  process,  as  a  means  of  checking  interbreeding  with  the  less- 
modified  parental  form,  which  might  linger  on  till  the  process 
was  almost  completed.  Now,  the  distinctive  recognition-mark 
seems  to  us  to  have  no  use ;  but  as  the  original  form  from  the 
adjacent  island  A  may  still  occasionally  visit  or  be  driven  to 
the  island  B,  it  would  now  be  treated  as  a  stranger,  and  thus 
prevent  the  better-adapted  form  being  deteriorated  by  inter- 
breeding with  the  less-adapted  immigTant. 


EECOGXITIOX-MAEKS  181 

Recognition  hy  Butterflies 

This  case  shows  how  easy  it  is  to  make  mistakes  or  arrive 
at  wrong  conchisions,  imless  we  take  account  of  all  the  de- 
tails of  a  problem,  and  endeavour  to  follow  out  the  exact  proc- 
esses of  nature  by  the  help  of  facts  known  to  us.  I  can 
say  this  with  more  confidence,  because  I  find  that  I  have 
myself  come  to  a  hasty  conclusion,  which  I  now  see  to  be  er- 
roneous, on  one  aspect  of  this  very  question ;  and  as  it  in- 
volves a  problem  of  some  importance  I  will  here  state  what  it 
is.  I  find  that  in  all  my  writings  on  this  subject  I  have  as- 
sumed, without  going  into  details,  that  the  theory  of  ^^  recog- 
nition-marks," which  so  well  accounts  for  a  very  widespread 
type  of  marking  and  coloration  in  birds  and  mammals,  is  also 
applicable  to  a  large  portion  of  the  markings  of  insects,  es- 
pecially in  the  case  of  butterflies.  But  a  little  consideration 
shows  that  there  is  no  resemblance  between  the  two  cases. 
Young  mammals  and  birds  grow  up  with  their  parents,  and 
get  to  know  their  appearance  in  every  detail.  They  also 
have  usually  brothers  and  sisters  growing  up  with  them,  so 
that  by  the  time  they  go  out  into  the  w^orld  to  care  for  them- 
selves they  are  thoroughly  acquainted  with  the  difference  be- 
tween themselves  and  other  species,  even  those  nearly  allied 
to  them.  This  complete  knowledge  is  increased  by  the  fact 
that  they  are  able,  through  the  mobility  of  the  head  and  neck, 
to  see  almost  every  part  of  their  own  bodies,  and  thus  know 
that  they  themselves  do  resemble  their  parents. 

But  with  the  butterflies,  and  most  other  insects,  everything 
is  different.  The  caterpillar  never  knows  its  parent,  and  when 
the  butterfly  emerges  from  the  pupa  and  takes  flight,  it  seems 
quite  impossible  that,  among  the  numerous  butterflies  of  all 
sizes,  shapes,  and  colours  that  it  may  immediately  encounter, 
it  can  possibly  know,  h^j  sight,  which  are  of  its  own  race.  Tt 
must  be  remembered  that  from  tlie  position  nf  its  eyes  if 
cannot  see  itself  except  at  so  oblique  an  angle  as  to  be  al- 
most useless;  and  when  we  consider  the  extreme  diversity  of 

7  t/ 


182  THE  WORLD  OE  LIEE 

the  sexes  in  many  butterflies  this  adds  to  the  difficulty  of 
supposing  vision  to  be  the  'primary  means  of  recognition.  But 
it  may  be  a  secondary  means.  It  is  well  known  that  in  some 
moths  the  females  attract  males  by  scores  at  night,  and  this 
can  only  be  by  scent,  or  something  analogous  to  it.  It  is 
also  known  that  the  males  of  manv  butterflies  emit  a  strong 
perfume  which  has  been  traced  to  certain  peculiarly  formed 
scales  on  the  wings.  Scales,  apparently  of  a  similar  nature, 
have  been  found  in  several  distinct  families  of  butterflies  and 
moths,  and  it  seems  probable  that  the  function  of  these  is 
in  all  cases  to  produce  a  perfume  agreeable  to  the  other  sex, 
though  only  in  a  few  cases  is  such  perfume  perceptible  to 
us. 

It  seems  probable,  therefore,  that  the  sexes  of  Lepidoptera 
are  mutually  attracted  by  a  perfume  agreeable  to  each  other, 
but  disagreeable  or  neutral  to  others  of  the  same  sex  or  to 
other  species.  Each  time  this  attractive  odour  was  perceived 
and  the  source  of  it  traced,  the  visual  image  of  the  insect 
would  be  connected  with  the  smell,  and  thus  only  would  the 
colour  and  markings  of  the  species  become  known  and  be 
distinguished  from  that  of  other  species.  This  being  the 
case,  we  see  that  the  complete  scaly  covering  of  so  many  of 
these  insects  serves  a  double  purpose.  It  affords  the  means 
of  using  an  extended  surface  for  the  highly  important  scent- 
glands,  which,  by  serving  to  bring  together  the  sexes  of  each 
species  and  to  prevent  intercrossing,  would  facilitate  differ- 
entiation and  lead  to  that  wonderful  diversity  of  colour  and 
marking  accompanying  comparatively  slight  differences  of 
structure  for  which  this  order  is  so  remarkable,  and  which  are 
absolutely  unequalled  in  the  whole  animal  kingdom.  This 
variety  of  colour,  rendered  possible  by  the  large  wing-surface 
covered  with  small  but  exquisitely  organised  scales,  is  util- 
ised for  securing  the  safety  of  the  perfect  insect  to  a  sufficient 
extent  to  provide  for  the  continuance  of  the  race,  thus  keep- 
ing up  that  endless  variety  of  form  and  colour  which  is,  per- 
haps, one  purpose  of  their  existence. 


KECOGNITIOX-MAliXS  183 

The  first  great  adaptation  here,  as  throughout  nature,  is 
to  secure  conceahnent  from  their  most  dangerous  enemies,  and 
this  is  effected  by  various  kinds  of  protective,  deceptive,  or 
-warning  coloration  which  in  some  form  or  other  pervades  the 
whole  order,  and  forms  a  most  fascinating  subject  of  study. 
The  protective  coloration  is  mostly  on  the  under  sides  of  the 
wings  of  butterflies,  and  on  the  upper  sides  of  the  upper  wings 
of  moths,  the  parts  respectively  exposed  to  view  when  the  in- 
sect is  at  rest.  Great  numbers  are  also  deceptively  coloured 
by  eye-marks  (ocelli),  which  resemble  the  eyes  of  mammals 
in  such  a  way  as  to  be  very  striking  in  the  mingled  light  and 
gloom  of  the  forest  and  in  the  general  surroundings  of  each 
species.  Large  groups  in  all  the  tropical  regions  possess  warn- 
ing colours,  either  very  bright  and  well  contrasted,  or  of  sober 
browns  and  yellows,  and  accompanied  by  such  elongated  wings, 
bodies,  and  antennae,  that  the  facies  of  the  whole  group  as 
well  as  of  the  individual  species  soon  become  known  to  in- 
sect-eating creatures. 

Those  which  are  protectively  or  deceptively  coloui-ed  on 
the  exposed  portions  of  their  wings  often  exhibit  the  most 
brilliant  or  gaudily  contrasted  colours  elsew^here;  but  in  these 
cases  the  flight  is  very  rapid  or  jerky,  and  the  insects  are  so 
continually  hidden  among  the  lights  and  shadows  of  the  forest, 
that  few  enemies  can  capture  them.  The  -  great  exj)anse  of 
the  wings  is  itself  an  additional  protection  by  diverting  at- 
tention from  the  body ;  and  it  has  thus  become  possible,  with- 
out endangering  the  continuance  of  the  species,  to  allow  the 
development  of  that  marvellous  display  of  colour,  the  charm 
of  which  can  only  be  fully  appreciated  by  those  who  have  for 
long  periods  sought  it  out  in  the  forest  regions  of  the  Amazon, 
of  the  Eastern  Himalayas,  or  of  the  Moluccas  and  Xew 
Guinea  —  the  three  most  productive  regions  in  the  world  for 
butterflies  (ajiS  also  for  birds)  of  resplendent  hues  and  in 
endless  variety. 


184  THE  WOKLD  OF  LIFE 

A  new  Alignment  against  Female  Choice 

Here  again  we  find  another,  and  I  think  a  very  conclusive 
argument  against  female  choice  having  had  any  part  in  the 
production  of  beautiful  and  varied  colours  in  the  males  of 
butterflies,  or  probably  of  any  insects,  since  it  is  clear  that 
the  attraction  is  through  another  sense  than  that  of  sight,  and 
all  that  vision  can  do  in  this  direction  is  to  enable  the  in- 
\  sect  to  recognise,  perhaps  at  a  greater  distance,  the  individuals 
which  are  thus  attractive.  There  is  much  evidence  to  support 
this  view.  H.  Miiller,  in  his  Fertilisation  of  Flowers,  states 
that  odour  is  pre-eminent  in  attracting  insects  to  flowers,  and, 
next  to  that,  general  conspicuousness  rather  than  any  special 
colour  or  form.  And,  by  his  detailed  accounts  of  insects 
visiting  flowers,  we  find  that  almost  all  the  commoner  butter- 
flies visit  a  great  variety  of  honey-bearing  flowers  W'ithout 
much  regard  to  colour.  Thus  Argynnis  papliia  visited  flowers 
of  four  different  natural  orders,  whose  flowers  w^ere  white  or 
pale  red ;  the  large  cabbage  butterflies  visited  seven  different 
orders,  including  red,  white,  purple,  yellow,  or  blue  flowers; 
the  small  tortoise-shell  visited  an  even  greater  range  of  flowers 
and  colours,  so  that  we  have  no  reason  to  impute  to  these  in- 
sects anything  more  than  the  power  to  recognise,  after  experi- 
ence, any  conspicuous  flowers  that  produce  pleasant  odours 
and,  usually,  accessible  honey. 

A  consideration  of  the  whole  evidence  as  to  the  purpose 
served  by  the  excessively  varied  and  brilliant  coloration  of  but- 
tei^ies  leads  us  to  the  conclusion  that  its  presence  is  due  to 
general  laws  of  colour-development  —  some  of  which  will  be 
discussed  in  later  chapters  —  whose  action  is  only  checked 
when  such  development  becomes  injurious.  In  the  case  of 
butterflies,  the  comparatively  short  period  that  elapses  between 
the  emergence  of  the  female  from  the  chrysalis  and  the  dep- 
osition of  her  eggs,  and  the  still  shorter  period  needed  for  the 
special  functions  of  the  more  brilliantly  coloured  male  to- 
gether wdth  his  power  of  irregular  but  rapid  flight,  render  it 


EECOGNITIOX-MAEKS  185 

possible  for  the  colour-development  to  attain  a  degree  of 
variety  and  beauty  beyond  that  of  all  other  living  things. 
The  larvae  of  Lepidoptera  in  their  countless  myriads  un- 
doubtedly constitute  an  important  factor  in  supporting  the 
gloriously  varied  bird-life  of  the  tropics,  as  we  have  seen 
that  they  so  largely  support  that  of  our  temperate  ^nes. 
It  is  the  comparatively  small  surplus  that  escapes  which  is 
yet  ample  for  the  development  of  the  perfect  insects  in  such 
abundance  as  to  keep  up  an  approximately  equal  supply  of 
larva?  for  the  next  generation  of  birds.  When  this  is  done  they 
themselves  become  the  prey  of  birds,  lizards,  and  other  insect- 
eating  animals. 

Some  General  Conclusions  from  Recognition-Marks 

We  have  thus  been  led  by  the  study  of  colour  as  a  means 
of  recognition  by  birds  and  mammals  to  some  very  important 
general  conclusions.  The  first  is,  that  in  both  these  groups, 
it  has  primarili/  a  still  more  important  function,  that  of  facili- 
tating the  formation  of  new  species  during  the  early  stages 
of  adaptation  to  changed  conditions  of  life.  Its  secondary, 
but  still  very  important  use  in  many  groups,  is  for  easy  identi- 
fication as  alreadv  described.  That  this  is  the  true  state  of 
the  case  is  rendered  almost  certain  by  the  occurrence  of  a 
large  number  of  species  in  which  the  markings  for  recognition 
are  noiv  unnecessary  though  they  were  of  the  highest  impor- 
tance during  the  initial  stages  of  evolution. 

Another  and  still  more  curious  result  of  the  study  of  this 
subject  is  the  evidence  it  affords  that  the  most  varied  in  colour 
and  markings  '  of  all  insects  —  the  butterflies  —  do  not,  pri- 
marily, recognise  each  other  by  sight,  but  by  some  sense 
analogous  to  that  of  smell.  This  seems  now  to  be  almost  cer- 
tain, and  it  affords  the  explanation  of  what  would  otherwise 
be  a  great  difficulty,  how  the  males  of  polymorphic  females,  as 
in  Papilio  pammon  in  the  East  and  Papilio  apneas  in  the  West, 
numerous  American  Pieridir  and  many  other  groups,  in  which 
the  females  are  coloured  as  if  with  the  purpose  of  being  as  un- 


186 


THE  WOKLD  OF  LIFE 


like  their  mates  as  possible,  are  able  to  recognise  each  other. 
Intuitive  knowledge  or  "  instinct "  is  now  given  up  by  every 
thinker;  but  the  proof  now  given  that  the  only  knoiun  method 
of  mutual  recognition  by  Lepidoptera  is  by  scent,  explains  the 
whole  difficulty.  The  colours  and  markings  of  these  insects 
have  been  produced  in  adaptive  relation  to  their  enemies  al- 
most exclusively,  and  this  explains  the  fact  that  the  strangely 
diverse  females  above  referred  to  are,  probably  in  every  case, 
either  protectively  coloured  or  mimics  of  distasteful  forms 
in  their  own  district.  The  fact  that  several  of  the  Eastern 
Papilios  have  fully  tailed  females  while  they  themselves  are 
round-winged,  is  another  indication  that  sight  can  have  no 
part  in  leading  to  mutual  recognition  between  the  sexes. 

The  almost  universal  presence  of  some  form  of  recognition- 
marks  in  birds  and  mammals,  no  less  than  the  proof  now  af- 
forded (and  for  the  first  time  stated)  of  their  entire  absence  in 
the  Lepidoptera,  affords,  I  think,  ample  justification  for  the 
importance  I  claim  for  them,  and  for  the  space  I  have  devoted 
to  them  in  the  present  volume. 


CHAPTER  X 

THE    EAETIl's    SURFACE-CHANGES    AS    THE    CONDITION    AND 
MOTIVE-POWER    OE    ORGANIC    EVOLUTION 

Having  now  sketched  in  outline  the  main  factors  on  which 
organic  evolution  depends  —  heredity,  variation,  and  rapid 
powers  of  increase  —  and  having  shown  by  a  sufficient  nuni- 
ber  of  examples  that  these  factors  are  omnipresent  features  of 
organic  life,  only  varying  somewhat  in  the  proportions  of  their 
occurrence  in  different  species,  we  are  now  prepared  to  indi- 
cate the  conditions  under  which  they  have  acted  in  the  produc- 
tion of  those  numerous  changes  of  form  and  structure  which  we 
observe  in  the  various  forms  of  life. 

We  have  seen  (in  Chapter  VI.)  that  so  long  as  no  consid- 
erable changes  occur  in  the  inorganic  world,  the  effect  pro- 
duced by  the  constant  interaction  between  species  and  species, 
or  between  plants  and  animals,  results  in  changes  of  local  dis- 
tribution of  the  various  species  rather  than  in  any  important 
modification  of  the  species  themselves.  And  there  really 
seems  no  reason  why  such  changes  should  occur ;  because  when 
once  complete  or  sufficiently  complete  adaptation  to  conditions 
is  brought  about,  the  whole  of  the  organic  world  will  bo  in  a 
state  of  stable  equilibrium,  with  sufficient  elasticity  in  all  its 
parts  to  become  adjusted  to  all  minor  periodical  changes  of 
climate,  etc.,  by  temporary  changes  in  numbers,  and  by  the 
local  distribution  of  the  sliffhtlv  altered  numbers.  Once  such 
an  efpiilibrium  is  attained,  there  seems  no  reason  why  it  should 
not  be  permanent.  Xatural  selection  would  keep  up  the  suffi- 
cient adaptation  of  each  species,  but  would  not  tend  to  change 
them. 

Geology     proves     that     the     inorganic     environment  —  the 

187 


188  THE  WORLD  OF  LIFE 

earth's  surface  —  is  not  stable ;  but  that  very  considerable 
changes  in  climate,  in  the  contour  of  the  land  surface,  and 
even  in  the  minor  distribution  of  land  and  water,  have  con- 
tinually occurred  during  past  ages;  and  that  just  in  proportion 
to  the  evidence  for  such  changes  do  we  find  that  changes  have 
occurred  in  the  forms  of  life  inhabiting  every  part  of  the 
earth.  A  short  statement  of  the  nature  of  these  two  groups  of 
coincident  and  interdependent  changes  will  therefore  be  useful 
here. 

The  most  general  and  most  arresting  facts  of  world-history, 
revealed  by  geology,  are,  that  the  superficial  crust  of  the  earth 
consists  of  various  "  rocks  "  (including  in  this  term  every  kind 
of  inorganic  matter  of  which  the  crust  is  composed)  deposited 
in  more  or  less  regular  "  strata  "  or  layers,  one  above  another ; 
that  these  strata  are  sometimes  horizontal,  more  often  inclined 
at  various  angles  to  the  horizon,  and  even  occasionally  vertical; 
usually  continuing  at  about  the  same  angle  or  slope  for  many 
miles,  but  often  curved  or  waved,  or  even  crumpled  up  and 
contorted  in  remarkable  ways.  These  various  strata  consist  of 
many  distinct  kinds  of  rock  —  sandstones,  limestones,  clayey 
or  slaty  rocks,  metamorphic  or  gneissic  rocks ;  and  all  of  these 
give  distinct  evidence  of  having  been  deposited  in  water,  both 
from  mechanical  texture  and  the  arrangement  of  their  com- 
ponent particles,  and  also  by  frequently  having  embedded  in 
them  the  remains  of  various  organisms,  those  that  live  in  seas 
or  lakes  being  by  far  the  most  abundant  and  varied.  As  an 
example  of  this  abundance  we  may  mention  the  Barton  Cliffs 
on  the  Hampshire  coast  east  of  Christchurch,  where,  in  a  dis- 
tance of  a  few  miles,  over  a  thousand  distinct  species  of  the 
fossilised  shells  of  molluscs,  radiates,  and  other  marine  animals 
have  been  found. 

But  the  most  suggestive  fact  from  our  present  point  of  view 
is,  that  almost  eveiy  mountain-range  on  the  earth  presents  us 
examples  of  such  stratified  rock-strata,  often  with  abundant 
fossils  of  marine  animals,  at  enormous  heights  above  the  sea- 
level.      Such  are  found  in  the  Alps  at  8000  feet,  in  the  Andes 


EARTH  CHANGES  AND  EVOLUTION  189 

at  14,000  feet,  and  in  the  Himalayas  at  16,000  feet  elevation. 
Innumerable  cases  of  marine  fossils  at  lesser  heights  are  to  be 
found  in  every  part  of  the  world,  and  in  rocks  of  very  various 
geological  age.  But  the  causes  that  have  produced  these  great 
changes  of  level  are  still  obscure.  It  is  certain,  however,  that 
such  changes  have  been  exceedingly  gradual  in  their  operation, 
and  have  in  all  probability  been  of  the  same  general  nature  as 
those  going  on  at  the  present  day  —  such  as  the  earthquakes 
which,  at  irregular  intervals,  occur  all  over  the  world. 

There  is  one  very  instructive  mode  of  ascertaining  the  rate 
of  certain  changes  of  the  earth's  surface  which  was  first  pointed 
out  by  Mr.  Alfred  Tylor  more  than  half  a  century  ago,^  and  is 
generally  accepted  by  geologists  as  of  great  value.  The  sur- 
plus water  of  the  land  is  carried  into  the  sea  by  rivers,  each 
of  which  has  a  drainage  area  which  contains  a  certain  number 
of  square  miles.  By  careful  measurements,  it  is  possible  to 
ascertain  how  much  water  flows  away  every  year,  and  also 
how  much  solid  matter  is  suspended  in  the  water,  how  much  is 
chemically  dissolved  in  it,  and  how  much  is  pushed  along  its 
bed  at  the  mouth.  The  sum  of  these  three  quantities  gives  us 
the  cubic  yards  or  cubic  miles  of  solid  matter  denuded  from 
the  surface  of  each  river-basin  in  a  year;  and  from  this  amount 
we  can  easily  calculate  how  much  the  whole  surface  is  lowered 
each  year,  while  some  corresponding  area  of  the  adjacent  sea- 
bottom,  on  which  it  is  deposited,  must  be  proportionally  raised. 
These  measurements  have  been  very  carefully  made  for  a  num- 
ber of  large  and  small  rivers  in  various  parts  of  the  world,  and 
the  following  results  have  been  accepted  as  fairly  accurate  by 
Sir  A.  Geikie :  — 

The  Mississippi  lowers  its  basin  1  foot  in  6000  years. 


Ganges 

2358 

Hoang-Ho 

1464 

Rhone 

1528 

Danube 

6848 

Po 

729 

1  See  Phil.  Mag.,  April  1853. 


190  THE  WORLD  OF  LIFE 

We  can  easily  see  here  that  the  rapidity  of  denudation  is 
proportionate  to  the  height  and  extent  of  the  mountain-ranges 
in  which  the  river  has  its  sources,  combined  with  the  amount  of 
the  average  rainfall,  and  the  proportion  of  plains  to  uplands 
in  its  whole  basin.  The  Ganges  has  a  large  proportion  of  low- 
land plain  in  its  area;  the  Hoang-Ho  has  less,  and  therefore 
denudes  more  rapidly.  The  Danube  and  the  Mississippi  both 
drain  an  enormous  area  of  lowlands  where  denudation  is  slight, 
and  the  rainfall  of  both  is  moderate;  they  therefore  lower 
their  basins  slowly.  The  Po  drains  an  enormous  extent  of 
snowy  Alps  in  proportion  to  its  whole  basin,  and  in  conse- 
quence lowers  the  land  perhaps  more  rapidly  than  any  impor- 
tant river  on  the  globe.  On  the  whole,  we  may  take  these 
rivers  as  fairly  representative.  Their  mean  rate  of  denuda- 
tion is  very  nearly  one  foot  in  three  thousand  years,  and  we 
may  therefore,  till  more  complete  observations  are  made,  take 
this  as  a  measure  of  the  average  rate  of  denudation  of  most  of 
the  great  continents. 

Of  course,  the  rate  of  lowering  will  be  extremely  unequal, 
being  at  a  maximum  in  the  mountains  and  a  minimum  in 
the  plains,  where  it  may  not  only  be  nothing  at  all,  but  if 
they  are  flooded  annually  they  may  be  raised  instead  of 
lowered.  In  the  loftier  mountains  with  numerous  peaks  and 
precipitous  slopes  the  average  lowering  may  often  be  ten  times, 
and  sometimes  even  a  hundred  times,  the  mean  amount.  In 
such  districts  w^e  can  even  see  and  hear  the  process  continually 
going  on.  Under  every  precipice  there  is  a  more  or  less  ex- 
tensive mass  of  debris  —  the  "  screes  "  of  our  lake  district ; 
and  every  winter,  chiefly  through  the  action  of  rain  and  frost, 
the  rocks  above  are  split  off,  and  can  be  heard  or  seen  to  fall. 
Even  on  grassy  hills  after  a  few  hours'  downpour  of  rain,  in- 
numerable trickles  of  muddy  water  course  down  in  every  di- 
rection ;  while  every  streamlet  or  brook  —  though  usually  of 
water  as  clear  as  crystal  —  becomes  a  rapid  torrent  of  mud- 
laden  w^ater.  It  is  by  a  consideration  of  these  every-day  phe- 
nomena in  operation  over  every  square  yard  of  thousands  of 


EAETH  CHANGES  AND  EVOLUTIOiV         191 

square  miles  of  surface  that  we  are  able  to  understaucj  ami 
appreciate  the  tremendous  power  of  rain  and  rivers,  greatly 
assisted  by  frost,  in  the  disintegration  of  rocks,  which  lower 
the  whole  surface  of  the  land  at  such  a  rate  that,  if  we  had 
means  of  accurate  comparison  with  its  condition  a  few  thou- 
sand years  ago,  we  should  see  that  in  many  places  the  whole 
contour  and  appearance  of  the  surface  was  changed. 

When  this  mode  of  estimating  the  rate  of  subaerial  de- 
nudation was  first  applied  to  well-known  regions,  geologists 
themselves  were  surprised  at  the  result.  Eor  1  foot  in  three 
thousand  years  is  1000  feet  in  three  million  years,  a  period 
which  has  always  been  considered  very  small  in  the  scale  of 
time  indicated  by  geological  changes.  When  we  consider  that 
the  mean  height  of  all  Europe  (according  to  a  careful  esti- 
mate by  Sir  John  Murray)  is  a  little  under  1000  feet,  we  find, 
to  our  astonishment,  that,  at  the  average  rate  of  denudation, 
the  whole  would  be  reduced  almost  to  sea-level  in  the  very 
short  period  of  three  million  years,  while  all  the  other  great 
continents  would  be  reduced  to  the  condition  of  '^  pene-plains '' 
(as  the  American  geologists  term  it)  in  about  six  or  eight 
million  years  at  the  utmost.  It  is  quite  certain,  therefore, 
that  there  must  be  some  counteracting  uplifting  agency,  either 
constantly  or  intermittently  at  work,  to  explain  the  often-re- 
peated elevations  and  depressions  of  the  surface  which  the 
whole  structure  and  mechanical  texture  of  the  vast  series  of 
distinct  geological  formations  with  their  organic  remains,  prove 
to  have  taken  place. 

The  exact  causes  of  these  alternate  elevations  and  depres- 
sions, sometimes  on  a  small,  sometimes  on  a  gigantic  scale, 
have  not  yet  been  satisfactorily  explained  either  by  geologists 
or  physicists.  Two  of  the  suggested  causes  are  undoubtedly 
real  ones,  and  must  be  constantly  acting;  but  it  is  alleged  by 
mathematical  physicists  that  they  are  not  adequate  to  produce 
the  whole  of  the  observed  effects.  They  are  both,  however,  ex- 
ceedingly interesting,  and  must  be  briefly  outlined  here.  We 
require  first,  however,  to  trace  out  what  becomes  of  the  de- 


192  THE  WORLD  OF  LIFE 

nuded  matter  that  lowers  the  continental  snrfaces  at  so  rapid 
a  rate,  and  is  poured  into  the  sea  at  various  points  around 
their  coasts ;  and  this  is  the  more  necessary  because  recent  re- 
searches on  this  matter  have  led  to  results  as  surprising  as  those 
of  the  measurement  of  the  amount  of  denudation  bv  rivers. 

During  the  voyage  of  the  Challenger  round  the  world  for 
the  purpose  of  oceanic  exploration,  not  only  was  the  depth  of 
the  great  oceans  determined  by  numerous  lines  of  soundings 
across  them  in  various  directions,  but,  by  means  of  ingenious 
apparatus,  samples  of  the  sea-bottom  w^ere  brought  up  from  all 
depths,  and  especially  along  lines  at  right  angles  to  the  shore 
at  short  distances  from  each  other.  The  exact  physical  and 
chemical  nature  of  all  these  samples  was  accurately  determined, 
and  some  most  curious  results  were  brought  to  light. 

The  earlier  geologists  had  assumed,  in  the  absence  of  direct 
evidence  to  the  contrary,  that  the  suspended  matter  poured 
into  the  sea  by  rivers  was,  sooner  or  later,  by  means  of  winds 
and  waves  and  ocean  currents,  distributed  over  the  whole  of 
the  ocean  floors,  and  was  gradually  filling  up  or  shallowing 
the  oceans  themselves.  But  the  Challenger  researches  showed 
that  this  idea  was  almost  as  remote  as  possible  from  the  truth. 
The  actual  facts  are,  that  the  wdiole  of  the  land  debris,  with  a 
few  special  and  very  minute  exceptions,  are  being  deposited  on 
the  sea-bottom  very  near  the  shore,  comparatively  speaking, 
and  all  but  the  very  finest  material  quite  close  to  it.  Every- 
thing in  the  nature  of  gravel  or  sand,  of  which  so  much  of  the 
rocky  strata  consists,  is  laid  down  within  a  very  few  miles, 
only  the  finer  muddy  sediments  being  carried  so  far  as  from 
20  to  50  miles  from  land;  w^hile  the  very  finest  of  all,  under 
the  most  favourable  conditions,  rarely  extends  beyond  150  and 
never  exceeds  300  miles  from  land  into  the  deep  ocean.  Mr. 
A.  Agassiz  also,  has  found  that  the  extremely  fine  mud  of  the 
Mississippi  River  is  never  carried  to  a  greater  distance  than 
100  miles  from  its  mouth.  If  we  take  even  so  much  as  50 
miles  for  the  average  distance  to  which  the  denuded  matter  is 
carried,    w^e    find    the    whole    area    of    deposit    around    South 


EAKTH  CHANGES  AND  EVOLUTION         193 

America  to  be  60,000  square  miles.  But  the  area  of  that  con- 
tinent is  about  six  million  square  miles,  so  that  deposition  goes 
on  about  a  hundred  times  as  fast  as  denudation ;  while  over 
considerable  areas  where  the  deposits  are  of  a  sand}^  rather  than 
of  a  muddy  or  slaty  nature,  it  may  go  on  a  thousand  times  as 
fast.  This  is  a  most  important  fact  which  does  not  appear 
to  have  been  taken  into  full  consideration  by  geologists  even 
to-day. 

The  correlative  fact  as  to  the  ocean  bed  is,  that  over  the 
whole  of  it,  when  more  than  the  above-named  distances  from 
land,  what  are  called  "  deep-sea  oozes "  are  found.  These 
are  formed  almost  entirely  by  the  calcareous  or  silicious  skele- 
tons of  minute  organisms,  together  with  small  quantities  of 
decomposed  pumice  and  of  meteoric  or  volcanic  dust.  Along 
with  these  in  certain  areas  the  remains  of  larger  marine  ani- 
mals are  found,  especially  the  otoliths  (or  ear  bones)  of  whales 
and  the  teeth  of  sharks.  And  the  extreme  slowness  of  the 
deposit  of  these  oozes  is  shown  by  the  fact  that  it  is  often  im- 
possible to  bring  up  a  dredging  from  the  bottom  that  does  not 
contain  some  of  these  bones  or  teeth.  It  seems  as  if  much 
of  the  ocean  bed  were  strewn  with  them !  Now,  these  oozes, 
so  easily  recognised  by  their  component  materials  and  their  or- 
ganic remains,  form  no  part  of  the  upheaved  crust  of  the  earth 
on  any  of  our  continents.  This  is,  of  itself,  a  conclusive  proof 
that  oceans  and  continents  have  never  changed  places  in  the 
whole  course  of  known  geological  time;  for  if  they  had  done 
so  (as  is  still  maintained  by  many  rather  illogical  writers)  the 
epoch  of  submergence  would  be  indicated  by  some  fragments, 
at  least,  of  the  consolidated  ocean  ooze  which  must  once  have 
covered  the  whole  continental  area.^ 

1  For  a  full  discussion  of  this  question,  see  my  Darwinism,  chap,  xii.; 
Island  Life,  chaps,  vi.  and  x.;  and  Studies  Scientific  and  Social,  vol.  i. 
chap.  ii.  In  this  last  work  the  whole  argument  is  summarised  and  the 
numerous  converging  lines  of  evidence  pointed  out. 


194  THE  WORLD  OF  LIFE 

Thickness  of  the  Earth's  Crust 

We  now  have  to  consider  a  quite  different  set  of  phenomena 
which  have  a  very  important  bearing  on  the  causes  which  have 
produced  the  elevations  and  depressions  which  have  occurred 
over  much  of  the  land  surface  of  the  globe.  It  is  a  universal 
fact  that  as  we  descend  into  the  crust  of  the  earth  (in  deep 
wells  or  mines)  the  temperature  rises  at  a  tolerably  uniform 
rate,  which  is  found  to  be  on  the  average  one  degree  Fahr.  for 
eveiy  47%  feet.  This  rate,  if  continued  downwards,  would 
reach  the  temperature  of  melted  rock  at  a  depth  of  about  20 
miles.  Hot  springs  in  non-volcanic  countries  furnish  an  ad- 
ditional proof  of  the  high  temperature  of  the  interior.  Below 
the  depth  above  indicated  there  would  probably  be  some  miles 
of  rock  in  a  plastic  state,  while  irregularities  w^ould  result 
from  the  nature  of  the  rock,  some  being  more  easily  melted  than 
others. 

^ow,  it  has  been  ascertained  that  the  various  rocks  of  the 
crust  are  of  less  specific  gravity  in  the  solid  state  than  when 
they  are  liquefied,  so  that  the  crust  may  be  looked  upon  as 
actually  floating  upon  the  liquid  interior,  very  much  as  the 
polar  ice-sheets  float  upon  the  ocean.  A  curious  confirmation 
of  this  has  been  given  by  measurements  of  the  force  of  gravity, 
which  show  that  near  all  great  mountain  masses  gravity  is  di- 
minished, not  only  by  the  amount  due  to  the  mass  of  the  moun- 
tain itself,  but  to  about  double  that  amount.  This  is  so  uni- 
versally the  case  that  it  has  been  concluded  that  the  weight  of 
the  mountain  mass  is  supported  by  a  corresponding  mass 
forced  down  into  the  fluid  magma,  and  hence  termed  the 
^^  roots  of  the  mountains  " ;  just  as  every  lofty  iceberg  must 
have  a  mass  of  submerged  ice  about  nine  times  as  great  to  sup- 
port it  in  the  water.  This,  of  course,  proves  that  the  crust  is 
flexible,  and  that  just  as  any  portion  of  it  is  upheaved  or  made 
thicker  by  additions  above,  a  corresponding  increase  in  thick- 
ness must  occur  below  to  keep  it  in  equilibrimn. 

Thus  are  explained  the  ver^^  frequent  phenomena  of  hori- 


EARTH  CHANGES  AND  EVOLUTION         195 


o 


zontal  strata  occurring  in  similar  beds  for  thousands  of  feet 
thick,  while  each  successive  bed  must  have  been  formed  at  or 
near  the  surface.  Such  are  the  deposits  recently  formed  in  the 
deltas  of  great  rivers,  in  many  of  which  borings  have  been 
made  from  350  to  640  feet  deep,  with  indications  that  each 
successive  layer  was  formed  near  the  surface,  and  that  during 
the  entire  process  of  deposition  the  whole  area  must  have  been 
sinking  at  a  very  regular  rate.  This  can  best  be  explained 
by  the  weight  of  the  matter  deposited  causing  the  slow  sub- 
sidence. Exactly  similar  phenomena  occur  through  the  whole 
series  of  the  geological  formations  to  the  most  ancient ;  in  some 
cases  strata  eight  miles  in  thicloiess  showing  proofs  that  the 
very  lowest  beds  w^ere  not  deposited  in  a  deep  ocean,  but  in 
quite  shallow  w^ater  near  shore.  ^ 

Now,  as  w-e  have  seen  that,  over  many  areas  not  far  from 
shore,  deposition  may  occur  100  or  even  1000  times  as  fast 
as  denudation,  and  that  this  same  area  is  continuously  lowered 
by  the  weight  forcing  the  crust  downwards,  we  have  a  real 
and  efficient  cause  for  continuous  subsidence  and  the  forma- 
tion of  parallel  strata  of  enormous  thicknesses.  It  remains  to 
account  for  the  subsequent  upheaval  of  these  areas,  their  tilt- 
ing up  at  various  angles,  and  in  many  cases  their  being  frac- 
tured, curved,  or  contorted  often  to  an  enormous  extent  and 
in  a  most  fantastic  manner. 

Effects  of  a  Cooling  and  Contracting  Earth 

It  is  universally  admitted  that  the  earth  is  a  cooling  and 
therefore  a  contracting  body.  The  cooling,  however,  does  not 
take  place  by  conduction  from  the  heated  interior  through  the 
solid  crust,  the  temperature  of  which  at  and  near  the  surface 
is  due  wholly  to  sun-heat,  but  by  the  escape  of  heated  matter 
to  the  surface  through  innumerable  hot  or  warm  springs;  by  a 
continuous  flow  of  heated  gases  from  volcanic  areas;  and  fre- 
quent   outbursts   of   red-hot    ashes    or    liquid    lavas    from   vol- 

1  In  chapter  iii.  of  vol.  i.  of  my  Studies  Scientific  and  Social  I  have  given 
details  of  these  phenomena  on  the  highest  geological  authority. 


196  THE  WORLD  OF  LIFE 

canoes.  The  springs  bring  up  from  great  depths  a  quantity 
of  matter  in  solution,  and  the  whole  of  the  above-mentioned 
agencies  result  not  only  in  a  very  considerable  loss  of  heat,  but 
also  in  a  very  great  outflow  of  solid  matter,  which,  in  the  course 
of  ages,  must  leave  extensive  cavities  at  various  depths,  and 
thus  produce  lines  or  areas  of  weakness  which  almost  certainly 
determine  the  mode  in  which  contraction  will  produce  its  chief 
effects. 

As  the  outer  crust  for  a  considerable  depth  has  its  tem- 
perature determined  by  solar  heat,  and  also  because  the  tem- 
perature at  which  the  rocks  become  liquid  is  tolerably  uni- 
form, the  loss  of  heat,  causing  shrinkage  of  the  globe  as  a 
whole,  must  occur  in  the  liquid  interior;  and,  as  this  becomes 
reduced  in  size,  however  slowly,  it  tends  to  shrink  away  from 
the  crust.  Hence  the  crust  must  readjust  itself  to  the  in- 
terior, and  it  can  only  do  so  by  a  process  of  crumpling  up, 
owing  to  each  successive  concentric  layer  having  a  less  area 
than  that  above  it.  This  shrinkage  has  been  compared  with 
that  of  the  rind  of  a  drying-up  apple.  But  the  earth's  crust 
having  been  for  ages  subject  to  ever-varying  compressions  and 
upheavals,  and  being  formed  of  materials  which  are  of  un- 
equal strength  and  tenacity,  the  actual  results  will  be  exceed- 
ingly unequal,  and  the  inequalities  will  be  most  manifested 
along  or  near  to  certain  lines  of  weakness  caused  by  earlier 
shrinkage  due  to  the  same  cause. 

As  the  crust  will  be  of  greater  extent  than  the  contracted 
liquid  core  it  has  finally  to  rest  upon,  and  as  the  chief  effects 
of  contraction  are  limited  to  certain  directions  and  to  com- 
paratively small  areas,  and  if  the  less  fractured  and  more  rigid 
portions  settle  down  almost  undisturbed  upon  the  contracted 
interior,  then  considerable  areas  along,  or  parallel  to,  the  lines 
of  weakness  must  be  crumpled,  fractured,  and  forced  upward, 
and  thus  produce  great  elevations  on  the  surface,  though  small 
in  proportion  to  the  whole  dimensions  of  the  earth.  IN'ow,  the 
ocean  floors  are  enormous  plains,  except  that  they  have,  here 
and  there,  volcanic  islands  rising  out  of  them.     The  water  which 


EARTH  CHANGES  A:N'D  EVOLUTION         197 

covers  them  preserves  uniform  temperature,  whicli,  at  the  bot- 
tom, is  not  much  above  the  freezing  point  of  sea-water.  We  may 
conclude,  therefore,  that  they  are  very  nearly  stable.  Pen- 
dulum experiments  show  that  the  crust  below  these  oceans  is 
more  dense  than  the  subaerial  crust,  due,  probably,  to  the  uni- 
form pressure  and  temperature  they  have  been  subject  to  for 
geologic  periods.  We  may  assume,  therefore,  that  they  do  not 
become  crumpled  or  distorted  by  the  contraction  of  the  liquid 
earth  beneath  them.  The  great  plains  of  Eussia,  mostly  of 
Triassic  and  Jurassic  age,  consist  of  nearly  horizontal  strata, 
while  the  Alps  of  Central  Europe  are  greatly  upheaved  and 
contorted ;  and  the  same  difference  between  adjacent  areas  is 
found  in  the  United  States,  and  most  probably  in  all  the  great 
continents. 

Mathematical  physicists  have  calculated  the  possible  up- 
heavals that  could  be  produced  by  a  shrinking  crust  at  prob- 
able rates  of  contraction,  and  have  declared  them  to  be  too 
small  to  account  for  the  elevation  of  the  existing  land- 
masses  above  the  ocean  floors,  that  is,  for  the  whole  differences 
of  height  of  the  land  surfaces.  But  if,  as  the  Rev.  O.  Eisher 
suggests,  the  oceanic  basins  were  formed  at  an  early  stage  of 
the  earth's  consolidation,  by  the  separation  from  it  of  the  moon 
in  the  way  described  by  Sir  George  Darwun  and  accepted  by 
Sir  Robert  Ball ;  and  if  the  whole  wrinkling  effect  of  contrac- 
tion is  concentrated  on  a  few  lines  or  areas  of  weakness,  al- 
ways near  existing  mountains ;  and  further,  if  this  cause  of 
elevation  be  supplemented  by  the  continual  subsidence  of  large 
areas  along  the  margins  of  all  the  continents  by  the  weight  of 
new  deposits  producing  a  pressure  on  the  liquid  interior,  which 
must  result  in  upward  pressures  elsewhere,  then  it  seems  pos- 
sible that  a  combination  of  these  causes  may  be  sufficient. 

Yet  another  cause  of  elevation  has  recently  been  demon- 
strated. After  many  unsuccessful  attempts,  the  actual  ex- 
istence of  semi-diurnal  lunar  tides  ivithin  iJic  earth's  interior 
has  been  proved;  and  such  tides  must,  it  is  said,  generate  a 
vast  amount  of  heat,  culminating  at  tlio  bi-monthly  periods  of 


198 


THE  WORLD  OF  LIFE 


maximum  effect.  The  heat  thus  produced  would  be  greatest 
where  the  under  surface  of  the  crust  was  most  irregular,  that 
is,  under  the  land  surfaces,  and  especially  under  the  ^'  roots  of 
mountains  "  projecting  below  the  general  level.  Their  cumu- 
lative results  would,  therefore,  add  to  the  upward  forces  pro- 
duced by  contraction  along  lines  of  weakness.^ 

But  whether  the  various  forces  here  suggested  have  been 
the  only  forces  in  operation  or  not,  the  fact  of  the  repeated 
slow  elevations  and  depressions  of  the  earth's  surface  is  un- 
doubted. The  most  general  phenomenon  seems  to  have  been 
the  very  slow  elevation  of  gTcat  beds  of  strata,  deposited  one 
above  another  along  the  coasts  of  a  continental  mass,  or  some- 
times along  the  shores  of  inland  seas;  immediately  followed 
by  a  process  of  denudation  of  this  surface  by  rain  and  rivers, 
which,  as  the  elevation  continued,  carved  it  out  into  a  complex 
series  of  valleys  and  ridges  till  it  ceased  to  rise  farther.  The 
denudation  continuing,  the  whole  mass  became  worn  away  into 
lowland  plains  and  valleys.  Then,  after  a  long  period  of 
quiescence,  subsidence  began,  and  as  the  land  sank  beneath  the 
water  new  deposits  were  laid  down  over  it.  Sometimes  re- 
peated elevations  and  depressions  of  small  extent  occurred; 
while  at  very  long  intervals  there  was  great  and  long-continued 
subsidence,  and,  while  deeply  buried  under  newer  strata,  the 
older  masses  were  subjected  to  intense  subterranean  heat  and 
compression,  which  altered  their  texture,  and  often  crumpled 
and  folded  them  up  in  the  strangest  manner  conceivable. 
Then,  perhaps,  a  long  period  of  elevation  brought  them  up  and 
up,  till  they  were  many  thousand  feet  above  sea-level ;  and, 
when  the  superficial  covering  of  newer  beds  had  been  all  re- 
moved by  denudation,  the  folded  strata  were  themselves  ex- 
posed to  further  denudation,  and  all  the  strange  peaks  and 
ravines  and  rushing  cataracts  of  alpine  mountains  became  re- 
vealed to  us. 

1  This  sketch  of  the  internal  structure  of  the  earth,  as  affecting  elevation 
and  depression  of  its  surface,  is  fully  discussed  in  INIr.  0.  Fisher's  Physics 
of  the  Earth's  Crust,  a  popular  abstract  of  which  is  given  in  my  Studies 
Scientific  and  Social,  vol.  i.  chap.  iii. 


EAKTH  CHAKGES  AND  EVOLUTION         I'JO 

ThuSj  in  alternate  belts  or  more  extended  areas,  our  con- 
tinents have  been,  step  by  step,  built  up  throughout  the  ages, 
■with  repeated  alternations  of  sea  and  land,  of  mountain  and 
valley,  of  upland  plateaus  and  vast  inland  seas  or  lakes,  the 
indications  of  which  can  be  clearly  traced  throughout  the  ages. 
And,  along  with  these  purely  terrestrial  changes,  there  have 
been  cosmic  changes  due  to  the  varying  eccentricity  of  the 
earth's  orbit  and  the  precession  of  the  equinoxes,  loading  to 
alternations  of  hot,  short  summers  with  long,  cold  winters,  and 
the  reverse;  culminating  at  very  distant  intervals  in  warm  and 
equable  climates  over  the  whole  land  surface  of  the  globe ;  at 
other  shorter  and  rarer  periods  in  more  or  less  severe  "  ice- 
ages,"  like  that  in  which  the  whole  north  temperate  zone  was 
plunged  during  the  Pleistocene  period,  long  after  the  epoch 
when  man  had  first  appeared  upon  the  earth. ^ 

Long  Persistence  of  the  Motive  Power  thus  caused 

It  is  in  tliis  long  series  of  physical  modifications  of  the 
earth's  surface,  accompanied  by  changes  of  climate,  partly  due 
to  astronomical  revolutions,  and  partly  to  changes  in  aerial 
and  oceanic  currents  dependent  on  terrestrial  causes,  that  we 
find  a  great  motive  power  for  the  work  of  organic  evolution, 
the  mode  of  operation  of  which  we  now  have  to  consider. 

Before  doing  so,  however,  I  would  call  attention  to  the  fact 
of  the  very  extraordinary  complexity  and  delicacy  of  the 
physical  forces  that  have  continued  to  act  almost  uniformly, 
and  with  no  serious  break  of  continuity,  during  the  whole  vast 
periods  of  geological  time.  These  forces  have  always  been 
curiously  balanced,  and  have  been  brought  into  action  alter- 
nately in  opposite  directions,  so  as  to  maintain,  over  a  large 
portion  of  the  globe,  land  surfaces  of  infinitely  varied  forms, 
which,  though  in  a  state  of  continuous  flux,  yet  never  reached 
a  stationary  condition.  Everywhere  the  land  is  being  low- 
ered by  denudation  towards  the  sea-level,  and  part  by  part  is 

1  See  my  Island  Life,  chapters  vii.,  viii.,  and  ix.,  for  a  full  discussion  of 
the  causes  and  effects  of  glacial  periods. 


200  THE  WOKLD  OE  LIFE 

always  sinking  below  it,  yet  ever  being  renewed  by  elevatory 
forces,  whose  nature  and  amount  we  can  only  partially  deter- 
mine. Yet  these  obscure  forces  have  always  acted  with  so 
much  regularity  and  certainty  that  the  long,  ever-branching 
lines  of  plant  and  animal  development  have  never  been  com- 
pletely severed.  If,  on  the  other  hand,  the  earth's  surface  had 
ever  reached  a  condition  of  permanent  stability,  so  that  both 
degrading  and  elevating  forces  had  come  to  a  standstill,  then 
the  world  of  life  itself  would  have  reached  its  final  stage,  and, 
w^anting  the  motive  power  of  environmental  change,  would  have 
remained  in  a  state  of  long-continued  uniformity,  of  which  the 
geological  record  affords  us  no  indication  whatever. 

Readers  of  my  book  on  Man's  Place  in  the  Universe  will 
remember  how,  in  chapters  xi,  to  xiv.,  I  described  the  long 
series  of  mechanical,  physical,  and  chemical  adjustments  of 
the  earth  as  a  planet,  which  were  absolutely  essential  to  the 
development  of  life  upon  its  surface.  The  curious  series  of 
geological  changes  briefly  outlined  in  the  present  chapter  are 
truly  supplementary  to  those  traced  out  in  my  former  work. 
The  conclusion  I  drew  from  those  numerous  cosmic  adapta- 
tions was  that  in  no  other  planet  of  the  solar  system  were  the 
conditions  such  as  to  render  the  development  of  organic  life 
possible  upon  them  —  not  its  existence  merely,  which  is  a 
vastly  different  matter.  That  conclusion  seemed  to  many  of 
my  readers,  including  some  astronomers,  geologists,  and 
physicists,  to  be  incontestable.  The  addition  of  the  present 
series  of  adaptations,  whose  continuance  throughout  the  whole 
period  of  world-life  history  is  necessary  as  furnishing  the  mo- 
tive power  of  organic  development  and  adaptation,  not  only 
increases  to  an  enormous  extent  the  probability  against  the  de- 
velopment of  a  similar  ^^  world  of  life,"  culminating  in  man,  in 
any  other  known  or  reasonably  conjectured  planet,  but  af- 
fords, in  my  opinion,  an  exceedingly  powerful  argument  for  an 
overruling  Mind,  which  so  ordered  the  forces  at  work  in  the 
material  universe  as  to  render  the  almost  infinitely  improbable 


EAKTH  CHANGES  AND  EVOLUTION         20i 

sequence  of  events  to  which  I  have  called  attention  an  actual 
reality. 

Terrestrial  Temperature  Adjustments 

Among  the  many  wonderful  adjustments  in  the  human 
body,  and  in  that  of  all  the  higher  vertebrates,  none  perhaps 
is  more  complex,  more  exact,  and  apparently  more  difficult 
of  attainment  than  those  which  preserve  all  the  circulating 
fluids  and  internal  organs  at  one  uniform  temperature,  vary- 
ing onlj^  four  or  five  degrees  Fahr.,  although  it  may  be  ex- 
posed to  temperatures  varying  more  than  a  hundred  degrees. 
Hardly  less  wonderful  are  those  cosmical  and  physical  adjust- 
ments, which,  during  many  millions  of  years,  have  preserved 
the  earth's  surface  within  those  restricted  ranges  of  temper- 
ature which  are  compatible  with  an  ever-increasing  develop- 
ment of  animal  and  vegetable  life. 

Equally  remarkable,  also,  is  that  other  set  of  adjustments 
leading  to  those  perpetual  surface-changes  of  our  globe  which 
I  have  shown  to  be  the  motive  power  in  the  development  of 
the  marvellously  varied  world  of  life;  and  which  has  done  this 
without  ever  once  leading  to  the  complete  subsidence  of  any 
of  the  great  continents  during  the  unceasing  motions  of  ele- 
vation and  depression  which  have  been  an  essential  part  of 
that  great  cosmic  scheme  of  life-development  of  which  I  am 
now  attempting  an  imperfect  exposition. 

That  the  temperature  of  the  earth's  surface  should  have  been 
kept  within  such  narrow  limits  as  it  has  been  kept  during  the 
enormous  cycles  of  ages  that  have  elapsed  since  the  Cambrian 
period  of  geology,  is  the  more  amazing  when  we  consider  that 
it  has  always  been  losing  heat  by  radiation  into  the  intensely 
cold  stellar  spaces ;  that  it  has  always,  and  still  is,  losing  heat 
by  volcanoes  and  hot  springs  to  an  enormous  extent;  and  that 
these  losses  are  only  counteracted  bv  solar  radiation  and  the 
conservative  effect  of  our  moisture-laden  atmosphere,  which 
again  depends  for  its  chief  conservative  effect  on  the  enormous 


202  THE  WORLD  OF  LIFE 

extent  of  our  oceanic  areas.  That  all  these  agencies  should 
have  continued  to  preserve  such  a  uniformity  of  temperature 
that  almost  the  whole  land  surface  is,  and  has  been  for  count- 
less ages,  suitable  for  the  continuous  development  of  the  world 
of  life,  is  hardly  to  be  explained  without  some  Guiding  Power 
over  the  cosmic  forces  which  have  brought  about  the  result. 


1 

i 


i 


i 


CHAPTER  XI 

THE    PROGRESSIVE    DEVELOPMEITT    OF    THE    LIFE-WORLD^    AS 
SHOWN   BY    THE   GEOLOGICAL   RECORD 

In  order  to  form  any  adequate  conception  of  the  world  of 
life  as  a  whole,  of  the  agencies  concerned  in  its  development, 
and  of  its  relation  to  man  as  its  final  outcome,  we  must  en- 
deavour to  learn  something  of  its  past  history;  and  this  can 
only  be  obtained  by  means  of  the  fossilised  remains  preserved 
in  the  successive  strata  or  layers  of  the  earth's  crust,  briefly 
termed  "  the  geological  record."  In  the  preceding  chapter  I 
have  endeavoured  to  indicate  the  forces  that  have  been  at  work 
in  continually  moulding  and  remoulding  the  earth's  surface; 
and  have  argued  that  the  frequent  changes  of  the  physical  en- 
vironment thus  produced  have  been  the  initial  causes  of  the 
corresponding  changes  in  the  forms  of  organic  life,  owing  to 
the  need  of  adaptation  to  the  permanently  changed  conditions; 
and  also  to  the  opening  up  of  new  places  in  the  economy  of 
nature,  to  be  successively  filled  through  that  divergency  of 
evolution  which  Darwin  so  strongly  insisted  upon  as  a  neces- 
sary result  of  variation  and  the  struggle  for  existence. 

But  in  order  to  appreciate  the  extent  of  the  changes  of  the 
earth's  surface  during  the  successive  periods  of  life-develop- 
ment, it  is  necessary  to  learn  how  vast,  how  strange,  and  yet 
how  gradual  were  those  changes ;  how  they  consisted  of  alter- 
nate periods  of  not  only  elevation  and  depression,  but  also  of 
alternations  of  movement  and  of  quiescence,  the  latter  often 
continuing  for  long  periods,  during  which  more  and  more 
complete  adaptation  was  effected,  and,  perhaps  in  consequence 
a  diminished  preservation  in  the  rocks,  of  the  life  of  the  period. 
Thus  have  occurred  those  numerous  "  breaks  "  in  the  geo- 
logical  record   which   separate   the  great   "  eras "    and    "  sys- 

203 


204  THE  WORLD  OY  LIFE 

terns  "  of  the  geologist.  These  phenomena  are  admirably  ex- 
plained in  Professor  James  Geikie's  attractive  and  well-illus- 
trated volume  on  '^  Earth  Sculpture  or  the  Origin  of  Land 
Forms,"  published  in  1898.  Here  I  can  only  attempt  to 
sketch  in  outline  the  successive  stages  of  life  which  are  ex- 
hibited in  the  rocks,  and  point  out  some  of  their  most  striking 
features  with  the  conclusions  to  which  they  lead  us. 

During  the  latter  part  of  the  eighteenth  century  geologists 
were  beginning  to  obtain  some  detailed  knowledge  of  the 
earth's  crust  and  its  fossils,  and  arrived  at  a  first  rude  di- 
vision into  primitive,  secondary,  and  tertiary  formations. 
The  first  were  supposed  to  represent  the  epoch  before  life  ap- 
peared, and  comprised  such  rocks  as  granite,  basalt,  and 
crystalline  schists.  'Next  above  these  came  various  strata  of 
sandstones,  limestones,  and  argillaceous  rocks,  evidently  of 
aqueous  origin  and  often  containing  abundant  fossils  of 
marine,  fresh-water,  or  terrestrial  animals  and  plants.  The 
tertiary  were  clearly,  of  more  recent  origin,  and  contained 
shells  and  other  remains  often  closely  resembling  those  of  liv- 
ing animals.  It  was  soon  found,  however,  that  many  of  the 
rocks  classed  as  "  primitive "  either  themselves  produced 
fossils,  or  were  found  overlying  fossiliferous  strata;  and,  by  a 
more  careful  study  of  these  during  the  early  part  of  the  nine- 
teenth century,  the  three  divisions  were  more  precisely  limited 
—  the  first  or  '^  Primary,''  as  containing  the  remains  of  Mol- 
lusca,  Crustacea,  and  some  strange  fishes  and  amphibians; 
the  ''  Secondary,"  by  the  first  appearance  of  reptiles  of  many 
strange  forms ;  and  the  ^'  Tertiary,"  by  abundance  of  Mam- 
malia of  all  the  chief  types  now  existing,  with  others  of  new 
and  apparently  primitive  forms,  or  serving  as  connecting  links 
w^ith  living  groups. 

It  is  a  very  remarkable  fact,  not  sufiiciently  dwelt  upon  in 
geological  treatises,  that  this  first  grouping  of  the  whole  of 
the  life-forms  of  the  past  into  three  great  divisions,  at  a  time 
when  our  knowledge  of  extinct  animals  and  plants  was  ex- 
tremely scanty  as  compared  with  what  it  is  now,  should  still 


THE  GEOLOGICAL  RECORD  205 

be  in  universal  use  among  the  geologists  of  the  world.  The 
exact  limits  of  each  of  these  great  divisions  have  been  more  ac- 
curately determined,  but  the  abrupt  change  in  the  life-forms, 
and  the  world-wide  unconformity  in  the  stratification  on  pass- 
ing from  one  division  to  the  other,  are  as  great  as  ever.  Tlie 
Primary  or  Palaeozoic  period  is  still  that  of  fishes  and  Am- 
phibia; the  Secondary  or  Mesozoic,  that  of  reptiles,  in 
amazing  abundance  and  variety;  and  the  Tertiary  or  Caino- 
zoic,  that  of  an  almost  equal  abundance  of  Mammalia,  and 
with  a  considerable  variety  of  insects  and  birds. 

The  exceptions  to  the  generality  of  this  classification  are 
few,  and  are  particularly  interesting.  Of  the  myriads  of  rep- 
tiles that  characterise  the  Secondary  era,  only  two  of  the  nine 
orders  into  which  they  are  subdivided  have  been  found  so  far 
back  as  the  Permian,  the  latest  of  the  Palaeozoic  formations. 
One  of  these  most  primitive  reptiles  has  a  near  ally  in  the 
strange,  lizard-like  Hatteria  still  surviving  in  some  small 
islands  on  the  coast  of  l^ew  Zealand ;  while  others  which  seem 
to  form  connecting  links  with  the  earliest  mammals  may  be 
the  ancestral  form  from  which  have  descended  the  unique 
types  of  the  lowest  living  Mammalia,  the  omithorhynchus  and 
echidna  of  Australia. 

So  with  the  highest  type  of  vertebrates,  the  mammals. 
About  the  middle  of  the  nineteenth  century  small  mammalian 
jaws  with  teeth  were  discovered  in  w^hat  was  known  as  the 
dirt-bed  of  the  Purbeck  (Jurassic)  formation  at  Swanage; 
others  in  the  Stonesfield  Slate  of  the  same  fomiation;  and  at 
a  later  period  very  similar  remains  were  found  in  beds  of  the 
same  age  (and  also  in  the  Cretaceous)  in  Xorth  America. 
These  are  supposed  to  be  primitive  insect-eating  Marsupials 
or  Insectivora,  and  were  all  about  the  size  of  a  mole  or  a  rat; 
and  it  is  a  striking  example  of  the  imperfection  of  the  geo- 
logical record,  that  although  they  occur  through  the  whole 
range  of  the  Secondary  period,  from  the  Trias  to  the  Cre- 
taceous, their  remains  are  still  exceedingly  scanty,  and 
they  appear  to  have  made  hardly  any  structural  progress  in 


206  THE  WORLD  OF  LIFE 

that  enormous  lapse  of  time.  Yet  directly  we  pass  from  the 
Cretaceous  to  the  Tertiary  rocks,  not  only  are  Mammalia 
abundant  and  of  fairly  large  size,  but  ancestral  types  of  all 
the  chief  orders  occur,  and  such  highly  specialised  forms  as 
bats,  lemurs,  and  sea-cows  (Sirenia)  are  found  in  its  earliest 
division,  the  Eocene. 

Either  there  is  no  record  of  the  missing  links  in  the  Sec- 
ondary formations,  or,  what  is  perhaps  more  probable,  the 
break  between  the  Secondary  and  Tertiary  beds  was  of  such 
enormous  duration  as  to  afford  time  for  the  simultaneous  dvinsr 
out  of  numerous  groups  of  gigantic  reptiles  and  the  develop- 
ment in  all  the  large  continents  of  much  higher  and  more 
varied  mammals.  This  seems  to  imply  that  a  large  portion 
of  all  our  existing  continents  was  dry  land  during  this  vast 
period  of  time ;  the  result  being  that  the  skeletons  of  very  few 
of  these  unknown  forms  were  fossilised;  or  if  there  were  anv 
they  have  been  subsequently  destroyed  by  denudation  during 
the  depression  and  elevation  of  the  land  which  we  know  to 
have  occurred. 

We  will  now  consider  these  great  geological  periods  sep- 
arately, in  order  to  form  some  conception  of  the  changes  in 
the  world  of  life  which  characterised  each  of  them. 

The  Primary  or  Pdloeozoic  Era 

The  Palaeozoic  differs  from  the  two  later  eras  of  geology 
in  having  no  known  beginning.  The  earliest  fossils  are  found 
in  the  Cambrian  rocks ;  they  consist  of  a  few  obscure  aquatic 
plants  allied  to  our  Charas  and  Algae,  and  some  lowly  marine 
animals  allied  to  sponges,  crinoids,  and  annelids.  But  there 
are  also  many  forms  of  shell-bearing  Mollusca,  which  had  al- 
ready developed  into  the  four  great  classes,  lamellibranchs, 
pteropods,  gasteropods,  and  cephalopods ;  while  some  groups 
of  the  highly  organised  crustaceans  were  abundant,  being  rep- 
resented by  water-fleas  (ostracods)  and  numerous  large  and 
varied  trilobites.  Besides  these,  the  curious  Molluscoidea 
were  fairly  abundant,  Terebratulae  now  first  appear,  and,  as 


THE  GEOLOGICAL  EECORD  207 

well  as  the  genus  Lingnla,  have  continued  to  persist  through 
all  the  subsequent  ages  to  the  present  time.  Great  masses 
of  rocks  stratified  and  imstratified  exist  below  the  Cambrian, 
but  have  mostly  been  metamorphosed  by  internal  heat  and  pres- 
sure, and  contain  no  recognisable  organic  remains. 

Geologists  have  been  greatly  impressed  by  this  sudden  ap- 
pearance of  marine  life  in  such  varied  forms  and  compara- 
tively high  organisation,  and  have  concluded  that  the  strati- 
fied formations  below  the  Cambrian  must  probably  have 
equalled  the  whole  series  which  we  now  know  above  it.  Dr. 
Croll  declared,  that  "  whatever  the  present  mean  thickness  of 
all  the  sedimentary  rocks  of  our  globe  may  be,  it  must  be 
small  in  comparison  with  tlie  mean  thickness  of  all  the  sedi- 
mentary rocks  which  have  been  formed  " ;  while  Darwin  says, 
"  Consequently,  if  the  theory  be  true,  it  is  indisputable  that 
before  the  lowest  Cambrian  stratum  was  deposited  long  periods 
elapsed,  as  long  as,  probably  longer  than,  the  whole  interval 
from  the  Cambrian  age  to  the  present  day,  and  that  during 
these  vast  periods  the  world  swarmed  with  living  creatures."  ^ 
This  view  was  supported  by  Sir  Andrew  Eamsay,  Director- 
General  of  the  Geological  Survey,  who  possessed  unrivalled 
knowledge  of  the  facts  as  to  the  geological  record.  He  says, 
speaking  especially  of  the  fossil  fauna  of  the  Cambrian  age : 

"  In  this  earliest  known  varied  life  we  find  no  evidence  of  its 
having  lived  near  the  beginning  of  the  zoological  series.  In  a 
broad  sense,  compared  with  what  must  have  gone  before,  both 
biologically  and  physically,  all  the  phenomena  connected  with  this 
old  period  seem,  to  my  mind,  to  be  of  quite  a  recent  description; 
and  the  climates  of  seas  and  lands  were  of  the  very  same  kind 
as  those  the  world  enjoys  at  the  present  day."  - 

This  consensus  of  opinion  renders  it  highly  probable  that 
the  existing  geological  record  only  carries  us  back  to  some- 
where about  the  middle  of  the  whole  period  during  which  life 
has  existed  upon  the  earth. 

1  Origin  of  Species,  6th  ed.  p.  286. 
2proe.  Roy.  Soc.,  1874,  p.  834. 


208 


THE  WOELD  OF  LIFE 


Passing  through  the  long  series  of  Lower  Silurian  strata, 
(now  separated  as  Ordovician)  we  have  fuller  developments 
and  more  varied  forms  of  the  same  classes  found  in  the  Cam- 
brian; but  in  the  Upper  Silurian  we  meet  with  remains  of 
fishes,  the  first  of  the  great  series  of  the  vertebrates  to  appear 
upon  the  earth.  Thej  are  of  strange  forms  and  low  type, 
mostly  covered  with  a  kind  of  plate-armour,  and  apparentlv 
without  any  lower  jaw.  Hence  they  form  a  separate  class  — 
Agnatha  (^^  without  jaws").  They  also  appear  to  have  had 
no  hard,  bony  skeleton,  as  the  only  parts  fossilised  are  the  outer 
skin  with  its  more  or  less  armoured  covering.  The  illustra- 
tion (Fig.  39)  shows  one  of  the  simpler  forms,  the  whole  sur- 


FiG.  39. —  Thelodus  scoticiis. 
From  Upper  Silurian,  Lanarkshire.     Half  nat.  size. 


(B.M.  Guide.) 


face  being  covered  with  small  quadrangular  flattened  tubercles. 
The  tail  is  somewhat  twisted  to  show  the  bi-forked  character. 
The  mouth  must  have  been  an  aperture  underneath  the  head. 
Good  specimens  of  these  are  rarely  preserv^ed. 

In  another  family,  Pteraspidse  (Fig.  40),  the  skin-tubercles 


Fig.  40, —  Pteraspis  rostrata. 
From   Old  Red    Sandstone    of   Herefordshire.     One-third    nat.    size.      (B.M.    Guide.) 


are  united   into  plates   and  scales,   while  the  head   is  covered 
with   a   dorsal   shield,   often   terminating  behind   in   a   spine ; 


THE  GEOLOGICAL  RECORD 


209 


and  there  is  often  a  smaller  shield  beneath.  A  separate  piece 
forms  a  projecting  snout. 

The  shields  of  these  fishes  are  often  preserved,  while  the 
complete  body  is  very  rare. 

Another  gi'oup    (Fig.   41)   has  the  head   shield   continuous 


Fig.  41. —  Ceplalaspis  murchisoni. 
From  Old  Red  Sandstone  of  Herefordshire.     About  half  nat.  szie. 


(B.M.   Guide.) 


or  in  two  pieces,  while  the  skin-tubercles  are  united  into  vertical 
plates  on  the  sides  of  the  body,  as  in  the  species  here  sho^vn, 
while  others  have  two  or  three  rows  of  plates. 

The  highest  group  of  these  primitive  fishes  has  the  head 
and  fore  part  of  the  body  covered  with  large  polygonal  bony 
plates.  As  these  died  out  in  the  Devonian  epoch  their  place 
was  taken  by  true  fishes,  having  an  ossified  skeleton,  a  movable 
lower  jaw,  gill-covers,  and  pairs  of  pectoral  and  anal  fins  rep- 
resenting the  four  limbs  of  reptiles  and  mammals.  The  ear- 
liest of  these  were  allied  to  our  sharks ;  and  at  each  succeeding 
geological  stage  a  nearer  approach  was  made  to  the  higher 
types  of  our  modern  fishes. 

Class  —  Pisces 


Fig.  42.— Protocercal  Tail. 
The  primitive  type  of  true  fishes,  having  a  lower  jaw  and  paired  fins.      (B.M.  Guide.) 


Fig.  43. —  Heterocercal    (unequal-lobed)    Tail. 
The  middle  type  of  true  fishes.      (B.M.  Guide.) 


210 


THE  WOKLD  OF  LIFE 


Fig.  44. —  Homocercal    (equal-lobed)    Tail. 

Modern  type  of  true  fishes. 

The  older  types  persist  in  some  of  the  lower  forms.      (B.M.  Guide.) 


This  advance  in  development  is  well  indicated  by  the 
gradual  changes  in  the  tail,  as  shown  in  the  accompanying 
figures  (42-44).  The  upper  one  is  the  oldest;  but  it  soon 
became  modified  into  the  second,  which  in  various  modifica- 
tions prevailed  throughout  the  Palaeozoic  and  most  of  the  Sec- 
ondary periods;  while  the  third  perfectly  symmetrical  type 
did  not  appear  till  near  the  end  of  the  latter,  and  only  became 
predominant,  as  it  is  now,  in  the  Tertiary  period.  Many  of 
the  earlier  forms  have  tails  which  are  quite  symmetrical  ex- 
ternally, but  show  a  slight  extension  of  the  vertebrae  towards 
the  upper  lobe.  All  three  forms  still  exist,  but  the  third  is  by 
far  the  most  abundant. 

In  the  highest  Silurian  beds  land-plants  allied  to  ferns  and 
lycopods  first  appear,  and  with  them  primitive  scorpions.  In 
the  succeeding  Devonian  and  Carboniferous  strata  an  ex- 
tremely luxuriant  land  vegetation  of  a  low  type  appeared  and 
covered  a  large  part  of  the  existing  lands.  This  supported  a 
large  variety  of  arthropods  as  well  as  true  insects  allied  to 
mayflies  and  cockroaches,  with  a  great  number  of  Crustacea. 
Here,  too,  we  come  upon  the  next  great  step  towards  the  higher 
land  animals,  in  the  appearance  of  strange  Amphibia  forming 
a  distinct  order  —  the  Labyrinthodontia.  They  appear  to 
have  outwardly  resembled  crocodiles  or  lizards,  and  were  rather 
abundant  during  the  Carboniferous  and  Permian  eras,  dying 
out  in  the  subsequent  Triassic. 

That  portion  of  the  Palaeozoic  series  of  strata  from  the 
Silurian  to  the  Permian,  during  which  a  rich  terrestrial 
vegetation  of  vascular  cryptogams  was  developed,  with  numer- 


THE  GEOLOGICAL  RECORD  211 

ous  fonns  of  arthropods,  insects,  primeval  fishes  and  am- 
phibians, comprises  a  thickness  of  stratified  rocks  somewhat 
greater  than  that  of  the  whole  of  the  Secondary  and  Tertiary 
strata  combined.  This  thickness,  which  can  ho  measured  with 
considerable  approach  to  accuracy,  is  generally  supposed  to 
afford  a  fair  'proportionate  indication  of  the  lapse  of  time. 

There  is  a  popular  impression  that  in  these  remote  ages  the 
forces  of  nature  were  more  violent,  and  their  results  more 
massive  and  more  rapidly  produced,  than  at  the  present  time; 
but  this  is  not  the  opinion  of  the  best  geological  observers. 
The  nature  of  the  rocks,  though  often  changed  by  pressure  and 
heat,  is  in  other  cases  not  at  all  different  from  those  of  subse- 
quent ages.  Many  of  the  deposits  have  all  the  characters  of 
having  been  laid  down  in  shallow  water,  and  in  several  cases 
footprints  of  Amphibia  or  reptiles  have  been  preserved  as  well 
as  impressions  of  raindrops,  so  exactly  corresponding  with  those 
which  may  be  seen  to-day  in  suitable  places,  that  we  cannot 
suppose  the  operations  of  nature  to  have  been  more  violent 
then  than  now.  All  our  great  coal  deposits  of  PalaBOzoic  age 
indicate  long,  and  often  repeated,  but  very  slow  depression  of 
large  areas  of  land,  with  intervening  periods  of  almost  perfect 
stability,  during  which  dense  forests  had  again  time  to  grow, 
and  to  build  up  those  vast  thicknesses  of  vegetable  matter 
which,  when  buried  under  successive  rock-strata,  became  com- 
pressed into  coal-seams,  usually  of  several  feet  in  tliickness. 

It  is  an  extraordinary  fact  that  in  all  the  great  continents, 
including  even  South  America  and  Australia,  coal-fields  are 
more  or  less  abundant  at  this  period  of  the  earth's  history. 
This  is  proved  by  the  identity  or  close  similarity  of  the  vege- 
tation and  animal  life,  as  well  as  by  the  position  of  the  coal- 
beds,  in  regard  to  the  strata  above  and  beneath  them.  It  is 
true  that  coal  is  also  found  in  some  Secondary  and  Tertiary 
strata,  but  these  beds  are  much  less  extensive  and  the  coal  is 
rarely  of  such  purity  and  tliickness ;  while  the  later  coal-fields 
are  never  of  such  world-wide  distribution.  Tt  seems  certain, 
therefore,  that  at  this  particular  epoch  there  Avere  some  spe- 


212  THE  WOELD  OF  LIFE 

cially  favourable  conditions,  affecting  the  whole  earth,  which 
rendered  possible  a  rapid  growth  of  dense  vegetation  in  all 
situations  which  were  suitable.  Such  situations  appear  to 
have  been  extensive  marshy  plains  near  the  sea,  probably  the 
deltas  or  broad  alluvial  alleys  of  the  chief  great  rivers ;  and  the 
special  conditions  were,  probably,  a  high  and  uniform  tem- 
perature, with  abundance  of  atmospheric  moisture,  and  a  larger 
proportion  of  carbon-dioxide  in  the  air  than  there  has  ever 
been  since. 

We  may,  in  fact,  look  upon  this  period  as  being  the  neces- 
sary precursor  of  the  subsequent  rapid  development  of  terres- 
trial and  aerial  animal  life.  A  dense  and  moisture-laden 
atmosphere,  obscuring  the  direct  rays  of  the  sun,  together  wdth 
a  superabundance  of  carbonic-acid  gas  and  a  corresponding 
scarcity  of  free  oxygen,  would  probably  have  prevented  the 
full  development  of  terrestrial  life  with  its  magnificent  culmi- 
nation in  such  examples  of  vital  activity  as  we  see  manifested 
in  the  higher  mammalia,  and  especially  in  the  more  perfectly 
organised  birds  and  insects.  In  this  first  and  most  widespread 
of  the  coal-making  epochs  we  see  the  results  of  a  world-wide 
and  even  cosmical  adaptation  which  influenced  the  whole  future 
course  of  life-development;  while  the  later  and  more  limited 
periods  of  coal-formation  have  been  due  apparently  to  highly 
favourable  local  conditions,  of  which  the  production  of  our 
deeper  peat  beds  are  the  latest  example. 

If  then,  as  I  am  endeavouring  to  show,  all  life  development 
—  all  organic  forces  —  are  due  to  mind-action,  w^e  must  postu- 
late not  only  forces  but  guidance;  not  only  such  self-acting 
agencies  as  are  involved  in  natural  selection  and  adaptation 
through  survival  of  the  fittest,  but  that  far  higher  mentality 
which  foresees  all  possible  results  of  the  constitution  of  our 
cosmos.  That  constitution,  in  all  its  complexity  of  structure 
and  of  duly  co-ordinated  forces  acting  continuously  through 
eons  of  time,  has  culminated  in  the  foreseen  result.  ISTo  other 
view  yet  suggested  affords  any  adequate  explanation ;  but  this 
vast  problem  will  be  more  fully  discussed  later  on. 


THE  GEOLOGICAL  EECORD  213 

This  earliest,  but,  as  some  think,  the  most  extended  period 
of  geological  time,  has  been  very  cursorily  touched  upon,  both 
because  its  known  life-forms  are  more  fragmentary  and  less 
generally  familiar  than  those  which  succeeded  them,  and  be- 
cause the  object  here  is  to  show  reasons  for  considering  it  as 
essentially  'preparatory  for  that  wonderful  and  apparently  sud- 
den burst  of  higher  life-development  of  which  we  will  now  en- 
deavour to  give  some  account. 

The  Mesozoic  or  Secondary  Formations 

When  we  pass  from  the  Palaeozoic  to  the  Mesozoic  era  we 
find  a  wonderful  change  in  the  forms  of  life  and  are  trans- 
ported, as  it  were,  into  a  new  world.  The  archaic  fishes 
wholly  disappear,  while  the  early  Amphibia  (Labyrinthodonts) 
linger  on  to  the  Trias,  their  place  being  taken  by  true  reptiles, 
which  rapidly  develop  into  creatures  of  strange  forms  and 
often  of  huge  dimensions,  whose  skeletons,  to  the  uninstructed 
eye  might  easily  be  mistaken  for  those  of  Mammalia,  as  in  fact 
some  of  them  have  been  mistaken.  The  earliest  of  these  new 
types,  somewhat  intermediate  between  Amphibia  and  reptiles, 
appear  in  the  latest  of  the  Palaeozoic  strata  —  the  Permian. 
These  are  the  Theriomorpha  (or  "beast-shaped''  reptiles), 
which  show  some  relationship  to  true  mammals  which  so  quickly 
followed  them  in  the  lowest  of  the  Mesozoic  strata. 

These  early  reptiles  already  show  a  large  amount  of  speciali- 
sation. Some  have  greatly  developed  canine  teeth,  almost 
equalling  those  of  the  sabre-toothed  tiger;  others  were  adapted 
to  feed  on  the  luxuriant  vegetation  of  the  period,  while  their 
short,  massive  limbs  made  them  almost  as  clumsy-looking  as 
the  hippopotamus.  These  strange  creatures  were  first  discov- 
ered in  the  Karoo  formation  of  the  Cape  Colony,  but  have  been 
found  in  a  few  places  in  India,  Europe,  and  Xorth  America, 
always  either  in  the  highest  Primary  (Permian)  or  lowest 
Secondary  formation  (Trias).  Pemains  of  allied  forms  have 
been  found  in  the  north  of  England  and  in  the  Trias  of  Elgin, 
Scotland.     Their  nearest  survivimr  relatives  arc  supposed  to 


214:  THE  WOKLD  OF  LIFE 

be  the  monotremes  (echidna  and  platypus)  of  Australia,  jet  in 
the  whole  series  of  stratified  rocks  of  Secondary  and  Tertiary 
times  no  intermediate  form  has  yet  been  discovered. 

A  complete  skeleton  of  one  of  the  largest  of  these  beast- 
shaped  reptiles  is  represented  here  (Fig.  45).  The  body  of  this 
strange  animal  was  nearly  seven  feet  long,  and  its  small  teeth 
show  it  to  have  been  a  vegetable  feeder.  The  total  length  of 
some  specimens  was  nearly  ten  feet,  and  the  immense  limbs 
were  apparently  adapted  for  digging,  so  that  in  loose  soil  it 
mav  have  been  of  subterranean  habits.  In  the  same  forma- 
tion  other  allied  but  much  smaller  species  were  found. 

Along  with  these  w^ere  many  creatures  of  the  same  general 
type,  but  as  clearly  carnivorous  as  the  others  were  herbivorous. 
About  a  dozen  distinct  genera  have  been  characterised,  and  as 
each  probably  comprised  several  species,  and  as  these  have  as 
yet  been  all  obtained  from  a  few  very  limited  areas,  it  is  quite 
possible  that  the  land  animals  of  the  Cape  Colony  at  that 
early  period  may  have  been  almost  as  numerous,  as  varied,  and 
as  conspicuous  as  they  are  to-day. 

The  two  skulls  here  figured  (Figs.  46  and  47)  are  of  very 
different  forms,  and  must  have  belonged  to  animals  about  the 


Fig.  46. —  Dicynodon  lacerticeps    (Order  —  Anomodontia). 
From  Karoo  formation  (Trias),  South  Africa.      One-third  nat.  size.      (B.M.  Guide.) 

size  of  wolves;  but  there  were  many  others  of  various  shapes 
and  sizes,  some  even  equalling  that  of  a  large  crocodile. 

But  at  the  same  epoch,  apparently,  Europe  and  North  Amer- 
ica were  equally  well  supplied  w^ith  these  strange  reptiles,     Ira, 


•iiopouBn.§i    aq;    jo   aouB.iBaddv    9iqi?qo.ij — -jc  -oij 


(•9pinjc)  'H'a)      "auids  i^uoiB  laaj  08  •q^Sueq;      •uiniS[aa;  Jo  uapiBa^i  eq;  mox^ 

•  ( siaudj. 
-jivasnudfi    uopounn^i)     .iuusouiq     snopocToq^ui.iQ     jo     iio;e[9>^s — -qo  -oij 


THE  GEOLOGliCAL  KECOiilJ  lM:. 

Europe  till  recently  only  a  few  isolated  bones  or  fragments  of 
skulls  bad  been  discovered,  but  about  five  or  six  years  ago  a 
rich  deposit  was  found  on  the  banks  of  the  river  Dwina  in 
^N^orthern  Kussia.      Tn  a  large  fissure  of  the   rocks  quantities 


Fig.  47. —  J^lusaurus  felinus  (Order  —  Anomodontia). 
From  Trias  (South  Africa).      Two-thirds  nat.  size.      (B.M.  Guide.) 

of  nodules  of  very  hard  rock  had  been  found,  and  being  easy 
to  obtain,  were  broken  up  for  mending  roads;  till  Professor 
Amalitzky  from  Warsaw,  visiting  the  spot,  found  that  each 
of  these  nodules  contained  well-preserved  fossils  of  extinct  ani- 
mals, which  proved  to  be  reptiles  of  the  very  same  group  as 
those  of  South  Africa.  Some  of  these  nodules  contained  a 
skull;  others  contained  the  whole  skeleton,  these  being  some- 
times eight  feet  long,  and  of  strange  forms  corresponding  to 
the  crushed  or  distorted  body  of  the  animal.  Thenceforth 
Professor  Amalitzky  devoted  himself  to  the  work  of  explora- 
tion by  the  aid  of  a  grant  from  the  Imperial  Academy  of  St. 
Petersburg.  The  nodules  are  taken  to  Warsaw,  where  ihey 
are  carefully  opened,  and  the  fossilised  bones  extracted, 
cleaned,  and  put  together.  Some  of  these  are  found  to  be 
almost  identical  with  those  of  South  Africa;  others,  quite 
distinct,  though  allied.  Fig.  48  represents  the  skull  of  a  huge 
carnivorous  reptile,  which  must  have  been  about  the  same  size 
as  the  herbivorous  Pariasauri  fabundantly  preserved  in  tho 
nodules),  upon  which  it  doubtless  preyed.     As  the  skull  is  two 


216  THE  WOKLD  OF  LIEE 

feet  long,  and  the  whole  head  and  body  about  nine  feet,  it  must 
have  far  exceeded  in  size  the  largest  lion  or  tiger,  and  prob- 
ably that  of  any  carnivorous  land  mammal  that  has  ever  lived. 

In  I^orth  America  these  reptiles  were  also  present  in  consid- 
erable abundance.  Some,  forming  the  sub-order  Theriodontia, 
were  allied  to  the  Pariasauri,  and  were  probably  herbivorous; 
while  the  Pariotrichida?  were  carnivores,  as  were  also  a  very 
distinct  family,  the  Clepsydropidse.  Of  this  latter  group  one 
1  genus,  Dimetrodon,  is  here  figured  as  restored  by  Sir  Ray 
Lankester  (Fig.  49).  This  is  supposed  to  be  allied  to  the  liv- 
ing Hatteria  of  New  Zealand.  These  strange  carnivorous  rep- 
tiles of  this  early  period  may  have  preyed  upon  numerous 
herbivores  which  have  not  been  preserved,  as  well  as  upon  the 
primitive  insects  and  land  Crustacea,  which  at  this  period  were 
probably  abundant. 

The  remarkable  thing  is,  that  some  hundreds  of  species  of 
varied  form  and  size,  herbivorous  and  carnivorous,  should  have 
been  gradually  developed,  arrived  at  maturity,  and  completely 
died  out,  during  the  comparatively  short  periods  of  the  Permian 
and  Trias,  or  the  interval  between  them. 

It  is  probable,  however,  that  these  transition  periods  really 
occupied  a  very  great  length  of  time,  since  all  known  reptiles 
seem  to  have  originated  during  this  era,  though  owing  to  unfa- 
vourable circumstances  the  connecting  links  have  rarely  been 
preserved.  The  singular  Chelonia  (turtles  and  tortoises)  ap- 
pear fully  formed  at  the  end  of  the  Trias  or  in  the  earliest 
Jurassic  beds,  as  do  the  crocodiles,  the  aquatic  Plesiosaurians 
and  Ichthyosaurians,  the  flying  Pterodactyls,  and  the  huge 
Dinosaurs.  All  these  have  more  or  less  obscure  interrelations, 
and  their  common  ancestors  cannot  well  be  older  than  the 
Permian,  since  the  preceding  Carboniferous  offered  highly 
favourable  conditions  for  the  preservation  of  the  remains  of 
such  land  animals  had  they  existed.  To  bring  about  the  modi- 
fication of  some  primitive  reptile  or  amphibian  into  all  these 
varied  forms,  and  especially  to  bring  about  such  radical  changes 
of  structure  as  to  develop  truly  aerial  and  truly  oceanic  rep- 


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Fig.  48. —  Skull    of   the   gigantic   Theriomorpli    Carnivorous    Reptile 

Inostransevia. 
From  Northern  Russia.      (Length  of  skull,  2  feet.)      Permian  or  Triassic  age.      This 
animal    was   probably    as    large    as    a    rhinoceros.      (From    Sir   Ray   Lankester's 
Extinct  Animals.) 


Fig.  49. —  Probable   Appearance    of    the   Therioniorj)!!    KcitliU'    Dinietroilon. 
From  the  Permian  of  Texas.      It  was  the  size  of  a  large  dog.      (From  Sir  Kay  Lan- 
kester's  Extinct  Animals.) 


THE  GEOLOGICAL  RECORD  217 

tiles,  must,  with  smy  reasonable  speed  of  change,  have  required 
an  enormous  lapse  of  time,  yet  all  these  had  their  origin  seem- 
ingly during  the  same  period.  Some  account  of  the  strange 
animals  whose  abundance  and  variety  so  especially  character- 
ised the  Secondary  period  will  now  be  given. 

Order  —  Dinosauria 

Some  of  the  best  known  of  these  reptiles  have  been  found 
in  our  own  country,  and  we  will  therefore  begin  with  the 
Iguanodon,  of  which  teeth  and  bones  were  found  near  Maid- 
stone (Kent)  by  Dr.  Mantell  in  the  early  part  of  the  last 
century,  but  no  complete  skeletons  have  been  found.  A 
closely  allied  species  from  Belgium  of  the  same  age  (the 
Wealden)  is  here  figured  (Fig.  50).  It  was  about  thirty  foot 
long,  and  is  believed  to  have  walked  chiefly  on  its  hind  feet, 
and  to  have  fed  upon  the  foliage  or  fruits  of  good-sized  trees. 
As  shown  in  the  restoration  of  the  animal  in  its  supposed  usual 
attitude  when  alive  (Fig.  51),  it  would  stand  about  fourteen 
feet  high.  The  fore-limbs  are  comparatively  small,  termi- 
nating in  a  hand  of  five  fingers,  the  thumb  being  represented 
by  a  bony  claw.  The  much  longer  hind  legs,  however,  have 
feet  with  only  three  toes,  much  resembling  those  of  running 
birds,  and  numerous  impressions  of  such  feet  have  been  found 
in  rocks  of  the  same  age,  hence  the  group  to  which  it  belongs 
has  been  named  Ornithopoda  or  '^  bird-footed.''  From  the 
character  of  these  it  seems  probable  that  the  animal  would 
walk  on  all  fours  and  leap  with  its  hind  legs  in  the  manner 
of  a  kangaroo. 

The  skull  as  shown  by  Fig.  52  is  three  and  a  half  feet  long, 
and  the  numerous  close-set  serrated  teeth  seem  well  adapted 
for  grinding  up  large  quantities  of  vegetable  matter.  The 
deep  compressed  tail  indicates  that  it  may  have  been  used  for 
swimming,  and  that  the  animal  frequented  lakes  or  marshes, 
and  perhaps  escaped  its  enemies  by  taking  to  the  water.  It 
appears  to  have  had  no  protective  armour. 

Another  group   was   named    Stegosauria,   "  plated    lizards," 


218 


THE  WORLD  OF  LIFE 


from  tlieir  protective  armour,  a  skeleton  of  whicli  Is  figured 
(Fig.  53).  It  has  long  bony  spines  on  the  shoulders,  which, 
if  bearing  a  horny  covering,  would  have  been  an  effective  pro- 
tection against  beasts  of  prey;  and  this  is  followed  by  a  row 


Fig.  52. —  Skull  of  I guanodon  bernissartensis. 
From  the  Wealden  of  Belgium.     Three  and  a  half  feet  long.      (B.M.  Guide.) 


Fig.  53. —  Skeleton  of  Armoured  Dinosaur  {Scelidosaurus  harrisoni). 
From  the  Lower  Lias   of   Charmouth,   Dorset.     Length   along  spine,   about  13  feet; 

height  as  drawn,  7  feet,      (B.M.  Giiide.) 


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THE  GEOLOGICAL  RECORD 


219 


of  bony  knobs  on  the  sides,  which  also  probably  carried  spines 
protecting  the  vital  organs.  A  row  of  similar  bones  along  each 
side  of  the  powerful  tail  may  also  indicate  spines,  which  would 
have  rendered  this  an  effective  weapon  against  an  encmv  from 
the  rear.  In  another  allied  species,  of  which  the  skull  is  hero 
shown  (Eig.  54),  there  were  two  enormous  horns  above  the 
eyes  and  a  smaller  one  upon  the  nose;  while  the  margin  of 


Fig.  54. —  Skull  of  Horned  Dinosaur   (Sterrolophus  flabellatus). 
From  the  Upper  Cretaceous  of  Wyoming,  U.S.A.      (B.M.  Guide.) 

the  bony  expansion  behind  seems  to  have  borne  a  row  of  spiny 
plates. 

As  an  illustration  of  how  these  huge  but  ratlior  w(>ak  vege- 
table feeders  ^vere  protected,  the  above  restoratiou  uiny  bo  use- 
ful, especially  w^hen  we  remember  that  the  species  above  tigured 
was  as  bulky  as  a  rhinoceros  or  elephant.  It  was  found  in 
the  Upper  Jurassic  strata  of  Xorth  America. 


We  now  come  to  some  of  the  largest  laud-auiiual>  which 
ever  lived  upon  the  enrth — the  Snuropodn,  or  liznrd-footed 
Dinosaur  —  and  these  were  more  or  less  amphibious.     One  of 


220  THE  WORLD  OF  LIFE 

the  most  singular  of  these  is  the  Brontosaunis,  the  skeleton  of 
which  is  here  represented.  It  is  said  to  have  the  smallest  head 
in  proportion  to  the  body  of  any  vertebrate  animal.  Pro- 
fessor O.  C.  Marsh,  who  discovered  it,  states  that  the  entire 
skull  is  less  in  diameter  or  weight  than  the  fourth  or  fifth 
neck  vertebra,  while  the  brain-cavity  is  excessively  small.  He 
says :  '^  The  very  small  head  and  brain  indicate  a  stupid  slow- 
moving  reptile.  The  beast  was  wholly  without  defensive  or 
offensive  weapons  or  dermal  armour.  In  habits  it  was  more 
or  less  amphibious,  and  its  remains  are  usually  found  in  local- 
ities w'here  the  animals  had  evidently  become  mired." 

A  creature  nearly  as  large  was  the  Cetiosaurus  leedsi,  from 
the  Oxford  clay  near  Peterborough,  of  which  the  left  hind  limb 
and  the  larger  part  of  the  tail  are  mounted  in  the  British 
Museum.  It  measures  10  feet  6  inches  high  at  the  hip,  and 
must  have  been  nearly  60  feet  long.  Still  larger  was  the  Amer- 
ican Atlantosaurus  immanis,  of  w^hich  only  fragmentary  por- 
tions have  been  obtained;  but  a  complete  thigh-bone,  6  feet 
2  inches  long,  is  the  largest  yet  discovered.  It  was  found  in 
the  Upper  Jurassic  strata  of  Colorado,  U.S.A. 

The  largest  complete  skeleton  is  that  of  the  Diplodocus  car- 
negii,  now  w-ell  known  to  all  who  have  recently  visited  the 
British  ^Natural  History  Museum,  where  a  model  of  it  is 
mounted,  as  shown  in  the  photographic  picture  of  it  here  repro- 
duced. It  is  SO  feet  in  length,  both  neck  and  tail  being  enor- 
mously long  in  proportion  to  the  body.  It  is  supposed  that  it 
would  have  been  unable  to  walk  on  land  except  very  slowly, 
and  that  it  inust  have  lived  chiefly  in  the  water  on  juicy  water- 
weeds,  which  its  very  weak  teeth,  as  shown  in  the  above  figure 
of  the  skull,  would  alone  have  been  such  as  it  could  graze  on. 
The  very  long  neck  would  have  enabled  it  to  gather  such  food 
from  moderately  deep  water.  The  brain  occupied  the  small 
space  between  and  behind  the  eyes  (Fig.  58). 

These  huge  reptilian  herbivora,  feeding  in  marshes,  lakes, 
or  shallow  seas,  w^ere  preyed  upon  by  the  numerous  crocodiles 
which  lived  throughout  the  same  j)criods  and  are  everywhere 


Fig.  od. —  Probable  Appearance  of  the  Jurassic  Dinosaur  Stegosaurus. 

The  hind  leg  alone  is  twice  the  height  of  a  well-grown  man. 

(From   Sir  Ray  Lankester's   Extinct   Animals.) 


1 1 


THE  GEOLOGICAL  RECORD 


221 


found  in  the  same  strata.  They  were  of  varied  forms  and 
sizes,  but  as  they  did  not  differ  much  in  appearance  from  the 
various  crocodiles  and  alligators  now  living  in  the  tropics  they 


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need  only  be  mentioned.  But  besides  these  there  were  true 
Dinosaurs  of  similar  shape  to  tlie  Tguanodon,  but  of  rather  less 
massive  form   and   with  strong  teeth   curved  backward,   which 


222 


THE  WORLD  OF  LIFE 


Avitli  tliolr  wicle-openlng  jaws  evidently  adapted  them  to  seize 
and  prey  ujDon  the  larger  land-reptiles.     These  form  the  Sub- 


FiG.  58. —  Skull  of  Sauropodous  Dinosaur    {Diplodocus) . 
From  the  Upper  Jurassic  of  Colorado,   U.S.A.     One-sixth  nat.  size.      (B.M.   Guide.) 


Fig.  59. —  Skull  of  a  Theropodous  Dinosaur  {Ceratosaurus  nasicornis). 
From  the  Upper  .Jurassic  of  Colorado,   U.S.A.      One  sixth  nat.   size.      (B.:\r.   Guide.) 

order  Theropoda,  or  beast-footed  Dinosaurs.      The  skull  of  one 
of  these  here  shown   (Fig.   59)   is  more  than  2  feet  long,  but 


f. 


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THE  GEOLOGICAL  EECORD  223 

no  complete  skeleton  has  been  jet  discovered.  The  allied 
Megalosaurus  was  found  by  Dr.  Bnckland  in  the  Weahh'ii 
beds  in  such  abundance  that  he  was  able  to  piece  together 
enough  of  the  skeleton  to  show  its  affinity  to  the  Iguanodon. 

Order  —  Sauropterygia 

We  now  come  to  the  group  of  aquatic  lizards  wdiich  abounded 
in  all  the  seas  of  the  Mesozoic  period  from  the  Trias  to  the 
Chalk.  They  had  lizard-like  heads,  powerful  teeth,  both  fore 
and  hind  limbs  converted  into  paddles,  and  often  with  a  dilated 
swimming  tail.  They  varied  much  in  size,  but  were  often 
very  large.  Plesiosaurus  cramptoni,  from  the  Upper  Lias  of 
Whitby,  w^as  22  feet  long,  but  some  species  from  the  Chalk 
formation  were  from  30  to  40  feet  long.  A  skull  and  jaws 
of  P.  grandis,  from  the  Kimmeridge  clay,  is  6  feet  long,  which, 
if  the  proportions  were  the  same  as  those  of  the  species  here 
represented  (Fig.  60),  w-ould  have  belonged  to  an  animal  nearly 
50  feet  long.  The  whole  group  w^as  extremely  varied  in  form 
and  structure,  but  all  w^ere  adapted  for  preying  upon  such 
aquatic  or  marsh-frequenting  animals  as  abounded  during  the 
same  period. 

Order  —  Ichthyopterygia 

All  the  members  of  the  preceding  order  have  the  paddles 
supported  by  a  complete  bony  foot  or  hand  composed  of  five 
separate  fingers  and  connecting  wrist-bones.  But  in  the  pres- 
ent order  the  adaptation  to  marine  life  is  more  perfect,  a  dorsal 
fin  and  bi-forked  tail  having  been  developed  (Fig.  61),  while 
the  bony  skeleton  of  the  four  limbs  often  consists  of  seven  or 
eight  rows  of  polygonal  bones  closely  fitted  together  as  shown 
in  the  drawings  here  reproduced  (Fig.  62  A,  B).  They  were 
also  remarkable  for  their  verv  larG:e  and  hiffhlv  oro-anised  eves, 
which,  with  the  lengthened  jaws  and  closely  set  sharp  teeth,  indi- 
cate a  perfect  adaptation  for  capturing  the  fishes  which  the  seas 
of  that  age  no  doubt  produced  iu  the  same  abundance  and  almost 
as  great  variety  as  our  own.      These  creatures  also  varied  uiuch 


224 


THE  WOKLD  OF  LIFE 


B 


in  size  and  shape,  one  from  the  Lower  Lias  of  Warwickshire 
being  22  feet  long,  but  detached  vertebra?  sometimes  indicate 

a  much  larger  size.  In 
the  older  Triassic  beds 
smaller  species  are  found 
which  were  less  completely 
aquatic ;  and  these  seem  to 
show  an  affinity  to  Am- 
23hibia  rather  than  to  rep- 
tiles, indicating  that  the 
two  aquatic  orders  may 
have  had  independent  ori- 
gins. 

Still  later,  in  the  Cre- 
taceous formation,  there 
were  other  aquatic  reptiles 
quite  distinct  from  all  the 
preceding,  and  more  al- 
lied to  our  living  lizards, 
having  well-formed  swim- 
ming feet,  but  snake-like 
bodies.  These  serve  to  in- 
dicate how  completely  the 
?'^-.?^-~?^S'H^,''''^  ^^^  and  Hind  (B)     reptiles  of  the  Secondary 

Paddles     of    Ichthyosaurus    intermedius.  ^ 

From    Lower    Lias    of    Lyme    Regis.      One-third     CpOCh     OCCUpicd     the     plaCC 
nat.    size.      (B.M.    Guide.)  n^^     ^     ^  ,^         T\r 

now  nlled  by  the  J\lam- 
malia,  somewhat  similar  forms  adapted  for  aquatic  life  being 
again  and  again  developed,  just  as  the  Mammalia  subsequently 
developed  into  otters,  seals,  manatees,  porpoises,  and  whales. 


Order  —  Ornithosauria 

We  come  finally  to  one  of  the  most  remarkable  developments 
of  reptilian  life,  the  bird-lizards,  more  commonly  known  as 
Pterodactyls,  which  accompanied  all  the  other  strange  forms 
of  reptilian  life  in  the  Mesozoic  period.  They  are  first  found 
a  little  later  than  the  earliest  Dinosaurs,  in  the  Lowc-r  Lias  of 


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Bavaria;  but  as  they  are,  even  then,  fully  developed,  though 
small,  there  must  have  been  a  long  series  of  intennediate  forms 
which  probably  reached  back  to  the  Triassic  if  not  to  the 
Permian  era. 


Fig.  63. —  Skeleton  of  Pterodactylus  spectahilis. 
From  the  Upper  Jurassic  of  Bavaria.     Nat.  size.     This  early  form  has  teeth  and  a 
very  short  tail,  and  the  body  was  not  larger  than  that  of  a  sparrow.      (B.M. 
Guide.) 

The  illustration  of  the  skeleton  of  one  of  these  early  forms 
on  this  page  is  of  the  natural  size  (Fig.  63),  Tt  shows  the 
greatly  elongated  fifth  finger  to  which  the  wing-membrane  was 
attached.  In  this  form  there  were  small  teeth  in  the  jaws,  and 
the  tail  was  very  short. 


OQfi 


THE  WORLD  OF  LIFE 


Fig.  64. —  Restoration  of  a  Long- Tailed  Pterodactyl  {Rhamphorhynchus 

'phyllurus ) . 

From  the  Upper  Jurassic  of  Bavaria.  (B.M.  Guide.)  Expanse  of  wings  more  than 
2  feet.  The  long  tail  has  a  terminal  web,  shown  in  casts  in  fine  lithographic 
stone. 


The  above  restoration  (Fig.  64),  shows  a  larger  species  from 
the  Jurassic  formation,  at  which  period  they  were  more  varied. 
This  had  a  very  long  tail  with  a  dilated  membrane  at  its  tip. 
Allied  species,  with  a  long  pointed  tail,  have  been  found  in 
the  Lias  of  Lyme  Regis,  and  also  at  Whitby. 


Fig.  65. —  Toothless  Pterodactyl    {Pteranodon  occidentalis) . 

From  the  Upper  Cretaceous  of  Kansas,   U.S.A.      (B.M.   Guide.) 


It  was  not  till  the  Cretaceous  period  that  the  Pterodactyls 
reached  their  greatest  size,  the  species  figured  here  having  an 
expanse  of  eighteen  feet ;  and  these  large  forms  have  a  pow- 
erful but  toothless  beak  (Fig.   65). 

Fragments   of  bone   from   the   English    Chalk   indicate   an 


THE  GEOLOGICAL  REC0RT3 


227 


equally  large  size.  The  backward  prolongation  of  the  head  is 
supposed  to  show  that  the  powerful  muscles  required  for  such 
immense  wings  were  attached  to  the  head.  This  is  rendered 
more  probable  by  the  skull,  nearly  4  feet  long,  of  another  still 
larger  species,  in  which  the  occipital  crest  projects  a  foot  back 
from  the  head,  and  which  Professor  ^Farsli  believes  had  a 
spread  of  wdng  of  20  or  even  25  feet  (Fig.  66). 


Fig.  66. —  Lateral  View  of  Skull  of  Pteranodon  longiceps. 

From  the  Cretaceous  of  North  America.  One-twelfth  nat.  size.  The  jaws  are  en- 
tirely without  teeth.  There  is  an  enormous  occipital  crest  (c)  projecting  far 
behind  the  occiput,  to  which  the  mirscles  for  flight  were  probably  attached;  (a) 
the  nares  and  pre-orbital  cavity;  (&)  the  orbit.  This  species  had  an  expanse 
of  wings  of  about  20  feet.      (From  Nicholson's  Manual  of  Palaeontology.) 


We  thus  see  that  during  the  Secondary  epoch  the  great  class 
Reptilia,  wdiich  had  originated  apparently  during  the  last 
stages  of  the  Primary,  became  developed  into  many  special 
types,  adapted  to  the  varied  modes  of  life  wdiich  the  higher 
warm-blooded  vertebrates  have  attained  in  our  own  time.  The 
purely  terrestrial  type  had  their  herbivora  and  carnivora  cor- 
responding to  ours  in  structure  and  habits,  but  surpassing  them 
in  size;  the  amphibious  or  marsh  species  surpassed  our  largest 
existing  crocodiles,  while  the  true  aquatics  almost  exactly  an- 
ticipated the  form  and  habits  of  our  porpoises  and  smaller 
whales.  The  air,  too,  was  peopled  by  the  strange  Pterodactyls 
which  surpassed  the  bats  in  powers  of  flight,  in  which  they 
almost  rivalled  the  birds,  while  they  exceeded  both  in  the  enor- 
mous size  thev  attained.  Considering  how  rare  must  have  been 
the  circumstances  which  led  to  tlie  preservation  in  the  rocks  of 
these  aerial  creatures,  we  may  conclude,  from  the  large  number 
of  species  known  to  us,  that  they  \u\\<\  have  been  extremely 
abundant   in   middle  and  late   ^Icsozuic   times,   and   that   they 


228  THE  WORLD  OF  LIFE 

occupied  almost  as  important  a  place  in  nature  as  do  tlie  birds 
now.  Yet  not  one  of  the  varied  forms  either  of  the  terrestrial 
Dinosaurs,  the  aerial  Pterodactyls,  or  the  aquatic  Sauroptery- 
gia  and  Ichthyopterygia  —  all  abounding  down  to  Cretaceous 
times  —  ever  survived  the  chasm  that  intervened  between  the 
latest  Secondary  and  the  earliest  Tertiary  deposits  yet  discov- 
ered. This  is  perhaps  the  most  striking  of  all  the  great  geolog- 
ical mysteries. 

One  more  point  may  here  be  noticed.  The  early  small- 
sized  Pterodactyls  arose  just  when  highly  organised  winged 
insects  began  to  appear,  such  as  dragon-flies  and  locusts,  soon 
followed  by  wasps,  butterflies,  and  two-winged  flies  in  Middle 
Jurassic  times ;  from  which  period  all  orders  of  insects  were 
no  doubt  present  in  ever-increasing  numbers  and  variety. 

It  is  interesting  to  note  further,  that  at  the  very  same  epoch 
in  which  we  find  this  great  increase  of  insect  life  there  ap- 
peared the  first  true  flowering  plants  allied  to  the  Cycads,  with 
which  they  were  till  quite  recently  confounded.  These  also 
must  have  rapidly  developed  into  a  great  variety  of  forms, 
since  in  the  later  Cretaceous  formation  in  many  parts  of  the 
world  true  flowering  plants,  allied  to  our  magnolias,  laurels, 
maples,  oaks,  walnuts,  and  proteaceous  plants,  appear  in  great 
abundance.  These  seem  to  have  originated  and  developed  very 
rapidly,  since  in  the  earliest  deposits  of  the  same  formation 
none  of  them  occur. 

Mesozoic  Mammalia 

There  is  perhaps  nothing  more  remarkable  in  the  whole 
geological  record  than  the  fact  of  the  existence  of  true  mam- 
mals contemporaneous  with  the  highly  diversified  and  abundant 
reptile  life  throughout  the  period  of  their  greatest  development 
from  the  Trias  to  the  Cretaceous.  They  were  first  discovered 
nearly  a  century  ago  in  the  Stonesfield  Slate  at  the  base  of  the 
Great  Oolite  in  Oxfordshire,  and  were  described  under  the 
names  Amphitherium  and  Phascolotherium  (Fig.  67).  About 
forty  years  later   a  considerable   number  of  similar   remains 


Fig.  67. —  Lower  Jaw  of  Phascolotherium  bucklundi. 
Prom   the    Stonesfield   Slate    (Lower   Jurassic),    Oxfordshire.      Outline    fig.    nat.    size. 

(B.M.   Guide.) 


c? 


Fig.  68. —  Lower   Jaw   and   Teetli    of   IS i><i Uic other ium   tricuspidcus. 
From  the  Purbeck  beds   (Upper  Jurassic)   of  Swanage.     Outline  fig.  nat.  size;  c  and 
d  being  lateral  and  upper  views   of  a   molar  tooth.      (B.if.   Guide.) 


f.ic  Vff  -x.^<~'   -^ — ^  ■_       .,--,,        .    fiiiiii   I  111   I    11  ^M"  -tmii 


Fig.  69. —  Lower  Jaw    oi  Ti  iconodon  fnoidujc. 
Purbeck  of  Swanage.     Nat.  size.      (B.M.  Guide.) 


THE  GEOLOGICAL  RECORD  229 

• — small  mammalian  jaws  with  teeth  —  were  found  in  what 
is  termed  the  dirt-bed  at  Swanage,  in  the  upper  part  of  the 
Jurassic  formation.  Two  of  these  —  Spalucotherium  and 
Triconodon  —  are  here  represented,  and  show  how  well  thej 
are  preserved  (Figs.  68  and  G9).  Another  of  a  different  type 
(Plagiaulax)  has  been  also  found  in  a  much  older  formation 
in  Somersetshire  —  the  Rhetic  or  Upper  Trias  —  and  in  beds 
of  the  same  age  in  Bavaria,  near  Wiirtemberg.  Both  these 
types  of  jaw  have  been  since  found  in  considerable  abundance 
in  the  Jurassic  beds  of  W^'oming,  U.S.A.  These  materials 
have  enabled  palaeontologists  to  decide  that  the  former  group 
were  really  of  the  marsupial  type,  while  the  latter  (and 
earlier  in  time)  belong  to  a  distinct  sub-class,  the  Multituber- 
culata,  from  the  curiously  tubercled  teeth,  resembling  those  of 
the  Australian  ornithorhvnchus.  Somewhat  similar  teeth  and 
jaws  have  been  found  also  in  the  Upper  Cretaceous  beds  of 
!N"orth  America. 

N^ow  it  is  quite  certain  that  these  small  mammals,  so  widely 
spread  over  the  northern  hemisphere,  must  have  been  devel- 
oped through  a  series  of  earlier  forms,  thus  extending  back 
into  that  unknown  gap  between  the  Palaeozoic  and  Mesozoic 
eras,  and  being  throughout  contemporaneous  ^vith  the  great  Age 
of  Reptiles  w^e  have  just  been  considering.  Yet  during  the 
whole  of  this  vast  period  they  apparently  never  increased  be- 
yond the  size  of  a  mouse  or  rat,  and  though  they  diverged 
into  many  varied  forms,  never  rose  above  the  lowly  types  of 
the  monotremes  or  the  marsupials !  Such  an  arrest  of  develop- 
ment for  so  long  a  period  is  altogether  unexampled  in  the  geo- 
logical record. 

The  Earliest  Birds 

Birds  present  us  with  a  similar  problem,  but  in  their  case 
it  is  less  extraordinary  because  their  ])reservation  is  so  much 
more  rare  an  event,  even  in  the  Tertiary  period,  when  we 
know  thev  must  have  been  abundant.  The  verv  earliest-known 
fossil  bird  is  from  the  Upper  Jurassic  of  Bavaria,  and  is  beau- 


230 


THE  WORLD  OF  LIFE 


Fig.   70.— Drawing  of  the   Fossil  Lizard-Tailed  Bird    {Arcliceopteryx 

macrura ) . 

From  the  lithographic   stone   beds  of  Bavaria    (Upper  Jurassic).      About   one-fourth 

nat.  size.     lu  the  Nat,  Hist.  Museum.      (B.M.  Guide.) 


THE  GEOLOGICAL  KECOliD  231 

tifully  preserved  in  the  fme-gi'aiued  beds  of  lithographic  stone. 
The  accompanying  ilhistration  is  from  an  exact  drawing  of  this 
specimen  (Eig.  TO),  in  order  to  render  more  distinct  the  details 
very  faintly  shown  in  the  original.  To  the  anatomist  every 
bone  or  fragment  of  a  bone  is  recognisable ;  while  the  mimis- 
takable  feathers,  and  the  foot  with  the  increasing  number  of 
joints  from  the  inner  to  the  outer  toe,  are  sufficient  to  show 
that  it  is  a  true  bird,  notwithstanding  its  curiously  elongated 
tail  feathered  on  each  side.  In  this  specimen  there  is  no  sign 
of  the  head ;  but  fortunately  another  specimen  has  recently 
been  found,  in  which  the  skull  is  well  preserved,  and  which 
shows  that  the  beak  was  armed  with  teeth  (Fig.  71).  Later 
on,  in  the  Cretaceous  for- 
mation of  Kansas,  U.S.A., 
some  well-preserved  aquatic 
birds  have  been  found. 
One  is  of  large  size  (about 
1  feet  high),  something  like 
a  diver,  but  with  flat 
breastbone,     and     therefore 

probably  with  rudimentary      Fig.    71.— Skull    of    Archwopteryx 
wings;         another,         much  ^  siemensi,   showing  Teeth. 

_  From  the  lithographic  stone   (Upper  Jurassic) 

smaller,        has       long       wing-  of   Bavaria.      Xat.    size.     Original    in    the 

1  1  11111  Berlin   Museum.      (B.]\r.    Guide.) 

bones  and  a  deeply  keeled 

sternum.      The  bonv  tail  of 

these  is  not  much  longer  than  in  living  birds,  but  in  both  the 

beaks  are  toothed. 

The  main  reason  for  the  extreme  rarity  of  bird-remains  in 
the  Mesozoic  era  is,  that  being  so  light  in  body  and  plumage 
they  could  very  rarely  be  presei'\Td.  Those  tliat  died  in  or 
on  the  margins  of  rivers  or  lakes,  or  wdiich  fell  into  the  water, 
would  be  at  once  devoured  bv  the  fishes  or  the  aquatic  or  aerial 
reptiles  which  seem  to  have  swanned  everywhere. 


232  THE  WORLD  OF  LIFE 

Concluding  Remarks  on  Mesozoic  Life-Development 

The  remarkable  series  of  facts  wliicL  have  now  been  sum- 
marised, and  which  have  been  largely  due  to  researches  in 
Xorth  America,  South  Africa,  and  Europe  during  the  last 
twenty  or  thirty  years,  are  of  such  a  nature  that  they  seem 
to  call  for  some  cosmical  explanation  similar  to  that  suggested 
to  account  for  the  vast  development  of  cryptogamous  vegetation 
towards  the  close  of  the  Palseozoic  era.  The  facts  are  in  many 
respects  strikingly  parallel.  We  find  in  the  Carboniferous 
series  of  rocks  a  storing-up  of  vast  masses  of  vegetable  matter 
in  the  form  of  coal,  which  is  unique  in  the  whole  past  history 
of  the  earth,  and  this  was  at  a  time  when  the  only  land  verte- 
brates  were  archaic  forms  of  amphibians.  Almost  immediately 
after  the  deposit  was  completed  true  reptiles  appeared  all  over 
the  earth,  and  rapidly  develoj^ed  into  that  "  Age  of  Eeptiles  " 
which  is  perhaps  the  greatest  marvel  of  geological  history. 
Birds  and  Mammalia  also  started  into  life,  apparently  branch- 
ing off  from  some  common  stock  with  the  reptiles.  Then, 
during  that  blank  in  the  record  separating  the  Secondary  from 
the  Tertiary  era,  the  whole  of  this  vast  teeming  mass  of  rep- 
tilian life  totally  disappeared,  with  the  two  exceptions  of  the 
crocodiles  and  the  tortoises,  which  have  continued  to  maintain 
themselves  till  our  own  day,  w^hile  true  lizards  and  snakes, 
which  are  not  known  in  earlier  times,  became  the  predominant 
forms  of  reptilian  life.  It  was  during  the  same  blank  period 
of  the  geological  record  that  mammals  and  birds  sprang  into 
vigorous  and  diversified  life,  just  as  the  reptiles  had  done 
during  the  blank  between  the  Primary  and  Secondary  eras. 
To  complete  the  great  series  of  life-changes  (perhaps  as  a  nec- 
essary preparation  for  them),  plants  underwent  a  similar  trans- 
formation; the  prominent  Cryptogams,  Conifers,  and  Cycads 
of  the  Secondary  era  gave  way  towards  its  close  to  higher  flow- 
ering plants,  which  thenceforth  took  the  first  place,  and  now 
form  probably  fully  99  per  cent  of  the  whole  mass  of  vegeta- 


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THE  GEOLOGICAL  EECOKD  233 

tion,  with  a  variety  of  nourishing  products,  in  foliage,  fruit, 
and  flower,  never  before  available. 

Now  here  we  have  a  tremendous  series  of  special  develop- 
ments of  life-forms  simultaneous  in  all  parts  of  the  earth, 
affecting  both  plants  and  animals,  insects  and  vertebrates, 
whether  living  on  land,  in  the  water,  or  in  the  air,  all  contem- 
poraneous in  a  general  sense,  and  all  determining  the  transi- 
tion from  a  lower  to  a  very  much  higher  grade  of  organisation. 
Just  as  in  the  first  such  great  step  in  advance  from  the  ''  age 
of  fishes  "  to  the  ''  age  of  reptiles  "  we  see  reason  to  connect 
it  with  the  change  from  a  more  carbonised  to  a  more  oxygen- 
ated atmosphere,  produced  by  the  locking  up  of  so  much  carbon 
in  the  great  coal-fields  of  the  world ;  so,  I  think,  the  next  groat 
advance  was  due  to  a  continuation  of  the  same  process  by  a 
different  agency.  Geologists  have  often  remarked  on  the  pro- 
gressive increase  in  the  proportion  of  limestone  in  the  later 
than  in  the  earlier  formations.  In  our  own  country  w^e  see  a 
remarkable  abundance  of  limestone  during  the  Secondary  era, 
as  shown  in  our  Lias,  Oolites,  Portland  stone,  and  Chalk  rocks ; 
and  somewhat  similar  conditions  seem  to  have  prevailed  in 
Europe,  and  to  a  less  extent  in  Xorth  America.  As  limestone 
is  generally  a  carbonate  of  lime,  it  locks  up  a  considerable 
amount  of  carbon  which  might  otherwise  increase  the  quantity 
of  carbonic  acid  in  the  atmosphere ;  and  as  lime,  or  its  metallic 
base,  calcium,  must  have  formed  a  considerable  portion  of  the 
original  matter  of  the  earth,  solid  or  gaseous,  the  continued 
formation  of  limestone  through  combination  with  the  carbonic 
acid  of  the  atmosphere  must  have  led  to  the  constant  diminu- 
tion of  that  gas  in  the  same  way  that  the  formation  of  coal 
reduced  it. 

It  seems  probable  that  when  the  earth's  surface  was  in  a 
greatly  heated  condition,  and  no  land  vegetation  existed,  the 
atmosphere  contained  a  much  larger  proportion  of  carb(m- 
dioxide  than  at  present,  and  that  a  continuous  reduction  of 
the  amount  has  been  going  on,  mainly  through  the  extraction 


234  THE  WOKLD  OF  LIFE 

of  carbon  from  the  air  by  plants  and  from  the  water  by  marine 
animals  and  by  chemical  action.  The  superabundance  of  this 
gas  during  the  early  stages  of  the  life-world  facilitated  the 
process  of  clothing  the  land  with  vegetation  soon  after  it  ap- 
peared above  the  waters;  while  its  absorption  by  water  was 
equally  useful  in  rendering  possible  the  growth  of  the  calcare- 
ous framework  or  solid  covering  of  so  many  marine  animals. 
With  the  progressive  cooling  of  the  earth  and  the  increased 
area  of  land-surface,  more  and  more  of  the  atmospheric  carbon 
became  solidified  and  inactive,  thus  rendering  both  the  air  and 
the  water  better  fitted  for  the  purposes  of  the  higher,  warm- 
blooded, and  more  active  forms  of  life.  This  process  will,  I 
think,  enable  us  partially  to  understand  the  fundamental 
changes  in  life-development  which  characterised  the  three  great 
geological  areas;  but  it  does  not  seem  sufficient  to  explain  tbe 
very  sudden  and  complete  changes  that  occurred,  and,  more 
especially,  the  almost  total  extinction  of  the  lower  or  earlier 
types  just  when  they  appear  to  have  reached  their  highest  and 
most  varied  structure,  their  greatest  size  of  body,  and  their 
almost  world-wide  distribution.  Before  attempting  a  solution 
of  this  difficult  problem  an  outline  must  be  given  of  the  latest, 
and  in  some  respects  the  most  interesting,  of  the  geological 
eras  —  the  Tertiary,  or,  as  more  frequently  termed  by  geolo- 
gists, the  Cainozoic. 


CHAPTER    XII 


LIFE  OF  THE  TERTIARY  PERIOD 


Directly  we  pass  from  the  Cretaceous  into  the  lowest  of  the 
Tertiary  deposits  —  the  Eocene  —  we  seem  to  be  in  a  new 
world  of  life.  Xot  only  have  the  whole  of  the  gigantic  Dino- 
saurs and  the  accompanying  swimming  and  flying  reptiles 
totally  disappeared,  but  they  are  replaced  in  every  part  (tf  the 
world  by  Mammalia,  which  already  exhibit  indications  of  being 
the  ancestors  of  hoofed  animals,  of  Carnivora,  and  of  Quadru- 
mana. 

Order  —  Ungulata 

In  the  Lower  Eocene  strata  of  ISTorth  America  and  Europe, 
the  sub-order  Condylarthra  is  well  represented.  These  were 
primitive,  five-toed,  hoofed  animals  which,  Dr.  A.  Smith  Wood- 
ward tells  us,  '"  might  serve  well  for  the  ancestors  of  all  later 
Uiigulata."  One  of  these,  Phenacodus  primcevus,  was  found 
in  the  Lower  Eocene  of  Wyoming,  U.S.A.,  and  was  about  4 
feet  long  exclusive  of  the  tail  (see  Eig.  72).  Considering  that 
this  is  one  of  the  very  earliest  Tertiary  mammals  yet  discov- 
ered, it  is  interesting  to  note  its  comparatively  large  size,  its 
graceful  form,  its  almost  full  series  of  teeth,  and  its  large  five- 
toed  feet;  affording  the  starting-point  for  diverging  modifica- 
tion into  several  of  the  chief  types  of  the  higher  mammalia. 
So  perfectly  organised  an  animal  could  only  have  been  one  of 
a  lono^  series  of  forms  brido:inc:  over  the  2:reat  c'ulf  between 
it  and  the  small  rat-like  mammals  of  the  ^lesozoic  period. 

Another  sub-order  is  the  Amblypoda,  of  which  the  Corypho- 
don  of  Europe  and  Xorth  Americn  is  one  of  the  best  known. 
This  was  about  6  feet  long,  and  was  first  obtained  from  our 

235 


206 


THE  WORLD  OF  LIFE 


London  Claj.  It  had  a  heavy  body,  five-toed  stumpy  feet, 
and  a  complete  set  of  22  teeth  in  each  jaw  adapted  for  a  vege- 
table diet ;  but  no  defensive  tusks  or  horns.  Other  allied  spe- 
cies were  much  smaller,  and  all  were  remarkable  for  a  very 

small  brain. 

But  a  little  later,  in  the  Middle  Eocene  of  North  America, 
they  developed  into  the  most  wonderful  monsters  that  have  ever 


Fig.  73. —  Uintatherium  ingens. 
Eocene  of  Wyoming,  U.S.A.     One-thirtieth  nat.  size.      (B.M.  Guide.) 

lived  upon  the  earth  —  the  Dinocerata  or  '^  terrible-horned  " 
beasts.  These  had  greatly  increased  in  size;  they  often  had 
large  tusks  in  the  upper  jaw ;  and  horns  of  varied  forms  and 
sizes  were  developed  on  their  heads.  The  tusks  were  some- 
times protected  by  a  bony  flange  projecting  downwards  from 
the  lower  jaw  immediatelv  behind  it,  as  well  sho^vn  in  the 
figure  here  given  of  Uintatherium  ingens.  This  animal  must 
have  been  about  11  feet  long  and  nearly  7  feet  high;  and  if 
the  six  protuberances  of  the  skull  carried  horns  like  our 
rhinoceroses,  it  must,  indeed,  have  been  a   ''  terrible  ''  beast, 


LIFE  OF  TERTIARY  PERIOD 


The  imperfect  skull  of  another  species  (Fig.  74)  shows  even 
larger  the  honj  horn-cores  presenting  all  tlie  appearance  of 
having  carried  some  kind  of  horns.  This  seems  the  more 
probable,  as  many  of  the  species  had  no  tusks,  and  in  that  case 
mere  rounded  bony  protuberances   would   have  been  of  little 


Fig.  74. —  Uintatherium  cornutum. 
From  the  Middle   Eocene  of  Wyoming,   U.S.A.      (Nicholson's   Palaeontology.) 

protective  use.  Figure  75  (on  p.  238)  represents  the  skeleton 
of  one  of  the  largest  species  without  tusks.  From  the  scah^ 
given,  it  must  have  been  11  or  12  feet  long  and  nearly  8  feet 
high. 

Professor  Marsh  informs  us  that  these  strange-homed  ani- 
mals have  been  found  onlv  in  one  Eocene  lake-basin,  in 
Wyoming,  U.S.A.     He  says: 

"These  gigantic  beasts,  which  nearly  equalled  the  elephant  in 
size,  roamed  in  great  numbers  about  the  borders  of  the  anciout 


238 


THE  WOKLD  OF  LIFE 


tropical  lake  in  which  many  of  them  were  entombed.  This  lake- 
basin,  now  drained  by  the  Green  Eiver,  the  main  tributary  of  the 
Colorado,  slowly  filled  up  with  sediment,  but  remained  a  lake  so 
long  that  the  deposits  formed  in  it  during  Eocene  time  reached  a 


LIFE  OF  TERTIAEY  PEETOD  239 

vertical  thickness  of  more  than  a  mile.  ...  At  the  present 
time  this  ancient  lake-basin,  now  6000  to  8000  feet  above  the  sea, 
shows  evidence  of  a  vast  erosion,  and  probabl}^  more  than  one-half 
of  the  deposits  once  left  in  it  have  been  washed  away,  mainly  by 
the  action  of  the  Colorado  River.  What  remains  forms  one  of 
the  most  picturesque  regions  in  the  whole  West,  veritable  mauvaises 
terres,  or  bad  lands,  where  slow  denudation  has  carved  out  cliffs, 
peaks,  and  columns  of  the  most  fantastic  shapes  and  colours.  This 
same  action  has  brought  to  light  the  remains  of  many  extinct 
animals,  and  the  bones  of  the  Dinocerata,  from  their  great  size, 
naturally  first  attract  the  attention  of  the  explorer." 

As  regards  the  mental  powers  of  these  strange  animals,  Pro- 
fessor Marsh  saj's: 

"  The  brain-cavity  of  the  Uintatherium  is  perhaps  the  most  re- 
markable feature  in  this  remarkable  genus.  It  shows  us  that  the 
brain  was  proportionately  smaller  than  in  any  other  known  mam- 
mal, recent  or  fossil,  and  even  less  than  in  some  reptiles.  It  is,  in 
fact,  the  most  reptilian  brain  in  any  known  mammal.  In  U.  mira- 
bile  (one  of  the  large- tusked,  horned  species)  it  could  apparently 
have  been  drawn  through  the  neural  canal  of  all  the  presacral 
vertebrae."  "^ 

It  was,  in  fact,  a  small  oval  mass  of  about  the  same  diameter 
as  the  spinal  cord ! 

One  other  strange  form  which  may  belong  to  the  earliest 
ungulates  has  been  found  in  the  Upper  Eocene  of  Egypt,  and 
forms  a  new  suborder,  Barjpoda.  It  is  known  from  a  very 
complete  skull  (Fig.  76),  which  is  remarkable  for  the  very 
regular  set  of  teeth,  as  well  as  for  the  wonderful  horn-cores, 
two  small  at  the  back  and  two  enormous  ones  projecting  in 
front.  The  skull  is  nearly  3  feet  long,  and  the  larger  horn- 
cores  about  2%  feet ;  and  as  these  certainly  carried  true  horns 
they  probably  surpassed  any  of  the  Dinocerata.  Large  quan- 
tities of  detached  bones  have  also  been  obtained,  sufficient  to 
show  that  the  creature  was  an  ungulate  of  elephantine  dimen- 
sions and  altogether  unique  in  appearance.  This  creature  hail 
a  somewhat  larsjer  brain  thnn   the  great  American   ungulates, 


240 


THE  WORLD  OF  LIFE 


and  has  affinities  with  a   curious  little  existing  animal,   the 
hyrax. 


Fig.  76. —  Skull  of  Arsinoitherium  zitteli. 
From  the  Upper  Eocene  of  the  Fayoum,   Egypt.      One-twelfth  nat.   size. 

(B.M.  Guide.) 


Order  —  Camivora 

These  can  also  be  traced  back  to  middle  or  late  Eocene 
times  both  in  l^orth  America  and  Europe.  They  were  mod- 
erate-sized animals,  forming  a  distinct  sub-order,  Creodonta, 
the  skeleton  of  one  of  which  is  shown  in  Fisr.  77.  Thev  had 
flesh-eating  teeth,  but  more  like  those  of  the  carnivorous  mar- 
supials of  Australia  than  of  our  living  carnivores,  with  a  type 
of  skeleton  showing  considerable  litrhtness  and  activity.  Some 
of  the  species  were  as  large  as  lions. 


LIFE  OF  TERTIAEY  PERIOD  241 

Some  of  the  older  remains  in  South  America,  called  Sparas- 
sodonta,  are  believed  to  belong  to  the  same  or  an  allied  sub- 
order. They  occur  in  beds  of  Lower  Miocene  age  in  Pata- 
gonia ;  and  Mr.  Lydekker  holds  them  to  be  "  undoubtedly 
marsupials,"  allied  to  the  Dasyuridic  of  Australia.  One  of 
these  has  been  named  Prothylacinus,  from  the  resemblance  of 
its  jaw  to  that  of  the  Tasmanian  wolf  (Thylacinus  australis). 
Other  small  species  forming  a  distinct  family,  Microbiothe- 
ridie,  he  also  thinks  were  probably  "  minute  polyprodont  mar- 
supials of  Australian  type."  ^ 

In  the  later  (upper)  beds  of  the  Eocene  formation  and  the 
early  or  middle  Miocene,  ancestral  forms  of  many  of  our  Mam- 
malia have  been  found  both  in  Europe  and  Xorth  America ; 
but  these  are  so  numerous,  and  their  affinities  in  some  cases 
so  obscure,  that  only  a  few  of  the  prominent  examples  need 
be  given.  One  of  these,  whose  skeleton  is  figured  on  page  243, 
belongs  to  the  family  Anthracotheridae,  which  has  affinities 
with  the  pigs  and  the  hippopotami,  of  which  it  seems  to  be 
an  ancestral  form.  The  fossil  remains  of  this  group  are  found 
in  deposits  of  middle  Tertiary  age  all  over  the  northern  hemi- 
sphere. They  have  two,  three,  or  four  separate  toes,  and  teeth 
much  like  those  of  swine. 

Another  family,  the  Anoplotheridae,  contains  a  variety  of 
animals  w^hich  seem  to  be  ancestral  forms  of  the  ruminants. 
The  genus  Anoplotherium  (Fig.  79)  was  one  of  the  most  re- 
markable of  these  in  having  a  full  and  continuous  set  of  teeth 
without  any  gaps,  like  that  of  the  Arsinoitherium  already 
figured. 

1  Geog.  Hist,  of  Mammals,  pp.  111-112.  From  these  facts  and  otliers  re- 
ferred to  in  my  preceding  chapter,  Mr.  Lydekker  thinks  that  "  it  is  difficnlt 
to  come  to  any  other  conclusion  than  that  the  ancestors  of  the  Santa  Crucian 
polyprotodont  marsupials  reached  the  country  either  by  way  of  the  Antarc- 
tic continent  or  by  a  land-bridge  in  a  more  northern  part  of  the  Pacific." 
To  avoid  a  break  of  connection  in  the  present  exposition,  I  have  briefly 
stated  some  of  the  difTieuliies  in  the  way  of  such  a  theory  in  an  Ap- 
pendix to  this  chapter.  Those  who  wish  to  see  the  whole  subject  of  the 
"  Permanence  of  Oceanic  and  Continental  Areas  "  more  fully  discussed  are 
referred  to  my  volumes  on  Darwinism  and  Island  Life. 


242 


THE  WORLD  OF  LIFE 


An  allied  family,  Oreodontidse,  somewhat  nearer  to  rumi- 
nants, but  with  four-toed  feet,  were  very  abundant  in  Xorth 
America   in   Miocene   times.     They  were   remotely   allied  to 


deer  and  camels,  and  were  called  by  Dr.  L-eidy  "  ruminating 
hogs."     They   seem   to   have   occupied   the   place   of   all   these 


LIFE  OF  TEKTIAEY  PEEIOD 


243 


animals,  six  genera  and  over  twenty  species  havlnp:  lieen  de- 
scribed, some  of  which  survived  till  the  earlv  Pliocene. 

The    family   Pala^otheridnc   was    also   abundant   during   tho 


244 


THE  WORLD  OF  LIFE 


same  period  in  Europe,  and  less  so  in  !N"orth  America.  As 
shown  in  the  restoration  in  Fig.  80,  it  somewhat  resembled 
the  tapir;  but  other  genera  are  more  like  horses,  and  show  a 
series  of  gradations  in  the  feet  towards  those  of  the  horse- 
tribe,  as  shown  bj  Hnxley's  figures  reproduced  in  my  Dar^vin- 


ism. 


The  Origin  of  Elephants 

Till  quite  recently  one  of  the  unsolved  problems  of  palaeon- 
tology was  how  to  explain  the  development  of  the  Proboscidea 
or  elephant  tribe  from  other  hoofed  animals.  Hitherto  extinct 
species  of  these  huge  beasts  had  been  found  in  a  fossil  state 
as  far  back  as  the  Miocene  (or  middle  Tertiary)  in  various 
parts  of  Europe,  Asia,  and  Xorth  America ;  one  species,  the 
mammoth,  being  found  ice-preserved  in  Arctic  Siberia  in  great 
quantities.  Some  of  these  w^ere  somewhat  larger  than  existing 
elephants,  and  several  had  enormously  large  or  strangely  curved 
tusks;  but,  with  the  exception  of  Dinotherium,  which  had 
the  lower  jaw  and  tusks  bent  downwards,  and  Tetrabelodon, 
with  elongated  jaws  and  nearly  straight  tusks,  none  were  very 
different  from  the  living  types  and  gave  no  clue  to  their  line 
of  descent.  But  less  than  ten  years  ago  a  number  of  fossils 
have  been  obtained  from  the  middle  and  higher  Eocene  beds 
of  the  Fayoum  district  of  Egypt,  which  give  the  long-hoped-for 
missing  link  connecting  the  elephants  with  other  ungulates. 

The  most  primi- 
tive form  now  discov- 
ered was  about  the 
size  of  a  very  large 
dog,  and  its  skull 
does  not  differ  very 
strikin2:lv  from  those 
of  other  primitive 
ungulates.  It  has, 
Fig.  81. —  Skull  of  Moeritherium  lyonsi.  however  some  slie'ht 
From  the  Middle  Eocene  cf  the  Fayoum,  Egypt.     One-  , .      '.    .  ,  ^   , 

seventh  nat.  size.      (B.M.  Guide.)  peculiarities         whlch 


Fig.  7!). —  Anoplotherium   commn/tie. 

Upper  Eocene    (Paris;    also   at  Binstead,  Isle   of  Wight.)      From  Nicholson's 

Palaeontology.) 

This  animal  was  about  the  size  of  an  ass,  and  was  especially  remarkable  fur  its 
continuous  set  of  44  teeth,  there  being  no  gap  in  the  series.  No  livins  mammal 
except  man  has  this  characteristic.  It  is  supposed  to  have  been  a  highly  spe- 
cialized  enrly   type   which   has   left   no   direct   descendants. 


Fj(;.   80. —  /'(ilaotherium   ntogntini. 
from  the  Upper  Eocene  of  Paris  and  the  Isle  of  "Wight.      (Nicholson's  PahuDntology.) 

The  numerous  species  of  Pala?otlierium  were  three-toed  animals  bavins  resembbmces 
to  horses,  tapirs,  and  llamas.  The  species  here  figured  (as  restored  by  Cuvier) 
was  about  the  size  of  a  horse,  but  it  is  now  known  that  the  neck  was  consid- 
erably  longer  than   here   shown. 


LIFE  OF  TEETIARY  PERIOD  245 

show  a  connection  with  the  Proboscidea.  These  are  that  the 
nasal  opening  is  near  the  end  of  the  snout,  indicating,  prohably, 
the  rudiment  of  a  proboscis;  the  back  of  the  skull  is  also  thick- 
ened and  contains  small  air-chambers,  the  first  step  towards  the 
very  large  air-chambers  of  the  elephant's  skull,  whose  purpose  is 
to  afford  sufficient  surface  for  the  powerful  muscles  which  sup- 
port the  weight  of  the  tusks  and  trunk.  The  teeth  show  two 
short  tusks  in  front  in  the  upper  jaw  in  the  same  position  as  the 
tusks  of  elephants,  while  the  lower  jaw  or  chin  is  lengthened 
out  and  has  two  incisor  teeth  projecting  forward.  The  molar 
teeth  show  the  beginning  of  the  special  characters  which  dis- 
tinguish the  huge  grinding  teeth  of  the  elephants.  This  crea- 
ture was  named  MoerWierium  lyonsi;  and  its  remains  have 
been  found  in  great  abundance  along  with  those  of  both  land 
and  sea  animals,  shoAving  that  they  were  deposited  in  what 
was  then  the  estuary  of  the  ISTile,  though  now  far  inland. 

Somewhat  later,  in  the  Upper  Eocene,  another  group  of 
animals,  the  Palseomastodons,  have  been  found,  showing  a  con- 
siderable advance  (see  Diagram,  Fig.  82).  They  vary  in  size 
from  a  little  larger  than  the  preceding  to  that  of  a  small  ele- 
phant. The  skull  is  very  much  modified  in  the  direction  of 
some  of  the  later  forms.  After  these  come  the  Tetrabelodons 
from  the  Miocene  beds  of  France  and  North  America,  and  the 
Pliocene  of  Germany.  These  w^ere  more  like  elephants  in 
their  general  form,  though  their  greatly  elongated  lower  jaw, 
bearing  incisor  teeth,  seem  to  be  developing  in  another  direc- 
tion. In  Tetrahelodon  longirostris,  however,  we  see  the  lower 
jaw  shortened  and  the  incisor  teeth  greatly  reduced  in  size; 
thus  leading  on  to  the  true  elephants,  in  which  these  teeth 
disappear. 

The  skeleton  of  Tetrahelodon  angustidens  shows  the  lower 
tusks  sliorter  than  the  upper  ones,  but  in  the  fine  specimen 
moimted  in  the  Paris  Museum,  and  photographed  in  Sir  Ray 
Lankester's  Extinct  Animals,  both  are  of  the  same  h^igth, 
and  the  upper  pair  curve  slightly  (hnvnwards  on  each  side  of 
the   lower   pair;    and   they   are   thus   shown    in   the   suggested 


246 


THE  WOKLD  OF  LIFE 


Recenl 

Pleistocene  ELE  PHA3 

( short  chinj 
Ufiper  Pliocene 


Lower  Pliocene 
Upjier  Miocene 


TETRABELODON 

[LONGIROSTRrS  STACE] 


(shortening  chinj 


Middle  Miocene    TETRABELODON 

fANCUSTTDENS  STAGE] 

lower  Miocene  (long  chinj 


l/frper  Oligocene 


Migration  from  Africa 
into  EuTvp.e  -Asia 


Imer  Oligocene? 
Upfier  Eocene 
MiddleBocene 
Lower  Eocene 


PALAEOMASTODON 
^lengthening  chinj 

MOERlTHEKrUM 
(short  chin) 


Fig.  82. —  Diagrams  showing  Increase  of  Size  and  Alteration  in  Form  of 
Skull  and  Teeth  of  the  Proboscidea  since  Eocene  Time.      (B.M.  Guide.) 


Fig.  83. —  Skeleton    of    Tetrahelodon    luigustidens. 
From  the  Middle  Eocene  of  Sansaus,  France.      (B.M.  Guide.) 


4 


4-i 

i 


A 


.;■  V 


•'*®*v,,  '^^ 


""^N, 


■•>-  --^j>- 


■  ^-»- . 


»AX 


Fig.  84. —  Probable    Appearance    of    Tetrahelodon    (HKjustidens. 
/From  Sir  Ray  Lankester's   Extinct  Animals.) 


LIFE  OF  TERTIARY  PERIOD 


247 


appearance  of  the  living  animal,  here  reproduced  from  his  book. 
(Fig.  84.)  The  trunk  could  not  therefore  have  hung  down 
as  in  the  modern  elephants,  and  it  seems  hardly  likely  that 
with  such  tusks  a  trunk  would  have  been  developed.  If  a  short 
one  had  been  formed  it  would  probably  have  been  for  the 
purpose  of  drinking  and  for  pushing  food  into  the  mouth  side- 
ways.    It   is  most   interesting  to   see   how   the   difficulty   was 


Fig.  85. —  Skeleton  of  Mastodon  Americanus. 
From  the  Pleistocene  of  Missouri,  U.S.A.      Length,  20  feet;   height,  9%   feet. 

(B.M.   Guide.) 

overcome.  In  the  next  stage  both  pairs  of  tusks  have  become 
straightened  out,  the  lower  ones  much  reduced  in  length  and 
the  chin  also  somewhat  shortened.  That  this  process  went  on 
step  by  step  is  indicated  by  the  ^lastodons,  which  are  elephants 
with  a  simpler  form  of  teeth,  and  a  pair  of  tusks  like  all  living 
and  recently  extinct  elephants  (see  Fig.  85).  But  when  very 
young  the  American  Mastodon  had  a  pair  of  short  tusks  in  the 
lower  jaw,  which  soon  fell  out.  In  the  character  of  its  teeth 
generally,  the  Mastodon  agrees  with  Tetrabelodon  (wliich  was 
originally  classed  as  a  Mastodon)  ;  and  there  are  Indian  extinct 


248  THE  WORLD  OF  LIFE 

species  which  show  other  stages  in  the  reduction  of  the  lower 
jaw. 

We  have  here,  therefore,  a  most  remarkable  and  very  rare 
phenomenon,  in  which  we  are  able  to  see  progressive  evolution 
upon  what  seems  to  be  a  wrong  track  which,  if  carried  further, 
might  be  disastrous.  Usually,  in  such  cases,  the  too  much 
developed  or  injuriously  developed  form  simply  dies  out,  and 
its  place  is  supplied  by  some  lower  or  less  modified  species  which 
can  be  more  easily  moulded  in  the  right  direction.  But  here 
(owing  probably  to  some  exceptionally  favourable  conditions), 
after  first  lengthening  both  lower  jaw  and  lower  tusks  to  keep 
pace  with  the  upper  ones,  a  reversal  of  the  process  occurs, 
reducing  first  the  lower  tusks,  then  the  lower  jaw,  till  these 
tusks  completely  disappeared  and  the  lower  jaw  was  reduced 
to  the  most  useful  dimensions  in  co-ordination  with  a  greatly 
lengthened  and  more  powerful  trunk.  Although  in  this  case 
the  gaps  are  still  rather  large,  there  can  be  no  doubt  that  we 
have  here  obtained  a  view  of  the  line  of  development  of  the 
most  remarkable  land  mammals  now  living  from  a  small  gen- 
eralised ungulate  mammal,  as  indisputable  and  as  striking  as 
that  of  the  horses  from  the  little  five-toed  Eohippus  of  the 
American  Eocene. 

It  may  be  here  mentioned  that  the  huge  American  Mas- 
todon has  been  found  in  the  same  deposits  with  stone  arrow- 
heads, and  was  undoubtedly  hunted  by  early  man;  as  was  also 
the  huge  mammoth  whose  beautifully  curved  tusks  form  its 
chief  distinction  from  the  living  Indian  elephant  (Eig.  86). 
This  species  is  abundant  in  the  frozen  mud  at  the  mouths 
of  the  Siberian  rivers;  and  in  some  cases  the  whole  body  is 
preserved  entire,  as  in  an  ice-house,  and  the  flesh  has  been 
sometimes  roasted  and  eaten  by  the  natives.  Remains  of 
skeletons  have  been  found  in  our  own  country  and  over  a  large 
part  of  Northern  Europe  and  Asia ;  while  its  portrait  has  been 
drawn  from  life  by  prehistoric  man,  either  upon  the  tusks 
themselves  or  upon  the  flat  portions  of  the  horns  of  reindeer 
which  he  hunted  for  food. 


LIFE  OF  TERTIAEY  PERIOD 


249 


5    « 


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u 

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rT   a 

1—1        o 
EC4 


Tertiary  Mammals  of  South  America  and  Australia 


ISTo  part  of  the  world  has  so  many  distinct  groups  of  !Mam- 
malia  peculiar  to  it  as  South  America,  among  wliioh  the  most 
remarkable  are  the  sloths  and  the  armadillos;  and  all  of  tlicm 
are  found  fossil  in  the  middle  or  late  Tertiary  or  the  Pleisto- 
cene, from  Brazil  to  Patagonia,  and  are  often  represented  by 
strange  forms  of  gigantic  size.  Some  account  of  these  will  now 
be  given.  DarAvin  was  one  of  the  first  collectors  of  these 
fossils  on  his  voyage  in  the  Beagle,  and  during  the  la:^t  twenty 


250 


THE  WOKLD  OF  LIFE 


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or  tliirty  years  niimerous  travellers  and  residents,  especially 
in  Argentina,  have  more  thoroughly  explored  the  deposits  of 


LIFE  OF  TERTIAKY  PEFaOD  251 

the  pampas  of  various  ages.  Their  great  richness  and  im- 
portance may  be  indicated  by  the  following  enumeration  of 
the  chief  orders  of  Mammalia  represented  in  them. 

Of  the  Peimates  (or  monkeys)  all  the  remains  are  of  the 
peculiar  American  families  Cebidas  and  Ilapalida:',  with  one 
extinct  genus  of  the  fonner.  Bats  (the  order  Chiroptera)  are 
abundant,  with  several  peculiar  genera.  The  Insectivora  arc 
very  rare  in  South  America,  but  a  fossil  has  been  found  sup- 
posed to  belong  to  the  peculiar  West  Indian  family  Solenodon- 
tidge.  The  Carnivora  are  chiefly  represented  by  fossils  of  the 
American  family  Procyonidse  (comprising  the  racoons  and 
coati-mundis),  of  which  several  extinct  genera  have  been  ol>- 
tained.  The  hoofed  animals  (Ungulata),  which,  from  tlieir 
great  abundance  in  a  living  state  in  every  part  of  the  world, 
and  their  habit  of  living  together  in  great  herds  often  of  many 
thousands,  have  been  most  frequently  preserved  in  a  fossil 
state,  are  here  represented  not  only  by  all  the  chief  forms  that 
still  inhabit  the  country,  but  also  by  some  which  are  now 
only  found  in  other  continents,  as  well  as  by  many  which  arc 
altogether  extinct.  Among  the  former  the  most  interesting 
are  true  horses  of  the  genus  Equus,  as  well  as  two  peculiar 
genera  of  ancestral  Equidge,  distinct  from  those  so  abundant 
in  I^orth  America.  There  are  also  several  ancestral  forms 
of  the  Llama  tribe,  one  of  which,  Macraiichenia  patacJionica, 
was  as  large  as  a  camel;  and  there  are  others  so  distinct  as  to 
form  a  separate  family  Proterotheriidse. 

Another  sub-order,  Astrapotheria,  were  more  massive  ani- 
mals, some  of  which  equalled  the  rhinoceros  in  size.  They 
consist  of  two  distinct  genera,  only  found  in  the  Patagouian 
deposits  of  Mid-Tertiary  age.-^ 

Still  more  remarkable  is  another  group  —  the  Toxodontia  — 
sometimes  exceeding  the  rhinoceros  in  bulk,  but  with  teeth 
which  approached  those  of  the  Rodentia;  of  these  there  are 
various  forms,  which  are  grouped  in  three  distinct  families. 
The  skeleton  of  one  of  the  most  remarkable  of  this  group  is 

iLydekker's  Geographical  History  of  Mammals,  p.  81. 


252  THE  WOELD  OF  LIFE 

shown  in  Fig.  87.  Yet  another  distinct  sub-order,  Pyrotheria, 
which  in  its  teeth  somewhat  resembled  the  extinct  European 
Dinotherium,  and  which  had  a  large  pair  of  tusks  in  the  lower 
jaw  is  found  in  the  earlier  Tertiary  strata  of  Santa  Cruz  in 
Patagonia.  The  elephants  also  had  a  representative  among 
these  strange  monsters  in  the  form  of  a  species  of  Mastodon, 
a  genus  also  found  in  North  America. 

The  very  numerous  and  peculiar  South  American  rodents 
commonly  called  cavies,  including  the  familiar  gniinea-pig,  are 
well  represented  among  these  fossils,  and  there  are  many  ex- 
tinct forms.  Most  of  these  are  of  moderate  size,  but  one, 
Megamys,  said  to  be  allied  to  the  viscachas,  is  far  larger  than 
any  living  rodent,  about  equalling  an  ox  in  size. 

Perhaps  more  remarkable  than  any  of  the  preceding  are 
the  extinct  Edei^tata  which  abound  in  all  these  deposits.  The 
entire  order  is  peculiar  to  America,  with  the  exception  of  the 
scaly  ant-eater  of  Asia  and  the  aard-vark  of  South  Africa,  and 
there  is  some  doubt  whether  these  last  really  belong  to  the  same 
order.  The  living  American  edentates  comprise  three  fam- 
ilies, generally  known  as  sloths,  ant-eaters,  and  armadillos, 
each  forming  a  well-marked  group  and  all  with  a  fair  number 
of  distinct  species.  But  besides  these,  two  extinct  families 
are  known,  the  Glyptodontidse  and  the  Megatheriidse,  the 
former  being  giant  armadillos,  the  latter  equally  gigantic  ter- 
restrial sloths.  Both  of  these  lived  from  the  Miocene  period 
almost  to  our  own  time,  and  they  are  especially  abundant  in 
Pliocene  and  Pleistocene  deposits.  Some  of  the  extinct  forms 
of  armadillo  were  very  much  larger  than  any  now  living;  but 
it  is  among  the  Glyptodonts,  which  had  a  continuous  shield 
over  the  whole  body,  that  the  largest  species  occurred,  the  shell 
being  often  6  or  8  feet  long.  The  skeleton  of  one  of  these  is 
represented  by  Fig.  88.  One  of  the  most  recent  (Dsedicurus) 
was  12  feet  long,  of  which  5  feet  consisted  of  the  massive 
armoured  tail,  which  latter  is  believed  to  have  borne  a  number 
of  movable  horns.  The  earlier  fossil  species  were  of  much 
smaller  size,  and,  though  far  more  abundant  in  the  south,  a 


LIFE  OF  TEETIARY  PERIOD 


few  of  them  have  been  found  in  the  Pliocene  deposits  of  Texas. 
The  extinct  ground-sloths  arc  even  more  remarkable,  since 


254  THE  WORLD  OF  LIFE 

they  were  intermediate  in  structure  between  the  living  sloths 
and  the  ant-eaters,  but  adapted  for  a  different  mode  of  life. 
Almost  all  are  of  large,  and  many  of  gigantic  size.  The  Mega- 
therium, which  was  discovered  more  than  a  century  ago,  was  one 
of  the  largest,  the  skeleton  (represented  by  a  cast  in  the  British 
Museum)  being  18  feet  long.  Their  massive  bones  show  enor- 
mous strength,  and  they  no  doubt  were  able  to  uproot  trees, 
by  standing  erect  on  the  huge  spreading  hind  feet  and  grasping 
the  stem  with  their  powerful  arms,  in  order,  to  feed  upon  the 
foliage,  as  shown  in  the  illustration  (Fig.  89).  The  jaw-bones 
are  lengthened  out,  indicating  extended  lips  and  probably  a 
prehensile  tongue  with  which  they  could  strip  off  the  leaves. 
An  allied  genus,  Mylodon,  which  is  somewhat  smaller,  has 
been  found  also  in  Kentucky  in  beds  of  the  same  age,  the 
Pleistocene. 

What  renders  these  creatures  so  interesting  is  that  they  sur- 
vived till  a  very  recent  period,  and  that  they  were  contemporary 
with  man.  Both  human  bones  and  stone  implements  have 
been  found  in  such  close  association  with  the  bones  or  skele- 
tons of  these  extinct  sloths  that  they  have  been  long  held  to 
have  lived  together.  But  a  more  complete  proof  of  this  was 
obtained  in  1897.  In  a  cavern  in  Patagonia,  in  a  dry  powdery 
deposit  on  the  floor,  many  broken  bones  of  a  species  of  Mylodon 
were  found ;  and  also  several  pieces  of  skin  of  the  same  animal 
showing  marks  of  tools.  Bpnes  of  many  other  extinct  animals 
were  found  there,  as  well  as  implements  of  stone  and  bone, 
remains  of  fires,  and  bones  of  man  himself.  Among  the  other 
animal  remains  were  those  of  an  extinct  ancestral  horse,  and 
on  some  of  the  bones  there  were  found  shrivelled  remains  of 
sinews  and  flesh. 

Allied  forms  are  found  in  older  deposits,  as  far  back  as  the 
Miocene,  but  these  are  all  of  smaller  size.  They  probably 
ranged  all  over  South  America,  and  the  two  genera  Megathe- 
rium and  Mylodon  occur  also  in  the  most  recent  deposits  of 
the  southern  United  States.  The  numerous  skeletons  in  the 
pampas  of  Argentina  are  usually  found  on  the  borders  of  old 


Fig.  89. —  Probable  Appearance  of  the  (iiant   Ground-Sloth 
( Megatherium   gigan  icnui ) . 

As  large  as  an  elephant.      Found  in  the  Pleistocene   gravels  of  South   America 
(From   Sir   Ray    Lankester's   Extinct   Animals,    p.    172.) 


Vic.  'JU. —  MyUxlon  robust ufi. 
From   the   Pleistocene  of   South   America.      ( Nicholson  s   Palii'ontohtpy. ) 


J 


J 


LIFE  OF  TERTIARY  PERIOD  255 

lakes  and  rivers,  in  the  positions  in  which  they  died.     Thrv 
are  supposed  to  have  perished  in  the  mud  or  quagmires  whih- 


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attempting  to  reach  the  water  for  drink  during  dry  seasons, 
great  droughts  being  prevalent  in  the  district;  but  when  these 


256  THE  WOKLD  OF  LIFE 

large  animals  lived  there  must  have  been  much  more  woody 
vegetation  than  there  is  now.  During  the  voyage  of  the  Beagle, 
Darwin  collected  a  large  quantity  of  these  interesting  fossils, 
as  described  in  his  JSTaturalist's  Voyage  round  the  World  (chap, 
v.).  The  skeleton  and  outline  figure  of  a  Mylodon  shown  in 
Fig.  90  was  11  feet  in  total  length,  but  other  species  were 
larger. 

A  remarkable  extinct  genus,  Scelidotherium,  of  which  the 
complete  skeleton  is  shown  in  Fig.  91,  was  about  10  feet  long, 
and  has  less  massive  limbs  than  the  Megatherium  or  Mylodon, 
and  more  elongated  jaws.  In  some  respects  it  approached  the 
ant-eaters,  and  was  probably,  like  them,  terrestrial  in  its  habits. 
About  twelve  distinct  genera  of  these  ground-sloths  are  now 
known,  comprising  a  large  number  of  species.  They  ranged 
all  over  South  America  and  into  the  warmer  parts  of  North 
America,  and  before  the  immigration  of  the  horse  and  the 
sabre-toothed  tiger  in  Pleistocene  times,  they  must  have  con- 
stituted the  larger  and  more  important  portion  of  the  mam- 
malian fauna  of  South  America. 

Extinct  Mammals  of  Australia 

The  existing  Australian  mammals,  although  of  varied  form 
and  structure,  are  almost  all  marsupials,  the  only  exceptions 
being  the  aerial  bats,  and  small  rodents  allied  to  rats,  which 
latter  might  have  entered  the  country  by  means  of  floating 
timber  or  trees  from  the  nearest  islands.  These  two  orders 
are  therefore  of  little  importance  geographically,  although  by 
counting  the  species  it  may  be  made  to  appear  that  the 
higher  mammals  (Placentalia)  are  nearly  as  numerous  as  the 
lower  (Marsupialia).  The  wild  dog,  or  dingo,  is  also  appar- 
ently indigenous,  but  it  may  have  been  introduced  by  early 
man,  as  may  some  of  the  rodents.  It  is  unfortunate  that  the 
deposits  of  Tertiary  age  in  Australia  seem  to  be  very  scanty, 
except  recent  gravels  and  alluvial  muds,  and  none  of  these 
have  produced  fossils  of  Mammalia  except  in  caves  and  dried- 
up  lakes,  which  are  all  classed  as  of  Pleistocene  age.     These, 


LIFE  OF  TERTIARY  PERIOD 


2:.7 


however,   are   very   productive   in   animal   remains   wliidi    arc 
extremely  interesting. 

They  consist  of  many  living  species,  but  with  them  numljers 
of  extinct  forms,  some  of  gigantic  size,  but  all  undoul)t(Mlly 
allied  to  those  living  in  Australia  to-day.  Thus,  bones  of 
kangaroos  are  found  ranging  in  size  from  that  of  the  smallest 
living  species  np  to  that  of  a  donkey,  and  sometimes  of  verv 
distinct  forms  and  proportions.  But  with  theso  have  been 
found  a  huge  wombat,  the  size  of  a  large  rhinoceros,  of  which 
the  skull  is  here  represented  (Fig.  92).     The  complete  skele- 


FiG.  92. —  Skull  of  an  Extinct  Marsupial,  Diprotodon  australis. 
From  the  Pleistocene  of  Queensland  and  South  Australia.      With  a   man's  skull,   to 

show  comparative  size.      (B.M.  Guide.) 


ton  has  been  quite  recently  obtained  from  Lake  Callabonna  in 
South  Australia.  It  is  found  to  be  12  feet  long  measured 
along  the  vertebrae,  and  6  feet  2%  inches  high.  As  it  has  been 
found  in  various  parts  of  the  continent,  it  was  probably  abun- 
dant. Another  smaller  animal  of  somewhat  similar  form 
was  the  Xototherium,  which  was  found  in  Queensland,  to- 
gether with  the  Diprotodon,  about  fifty  years  ago.  A  large 
phalanger  was  also  found,  which  Professor  Owen  called  the 
pouched  lion  {Tliylacoho  carnifex),  but  it  is  doubtful  whether 


258  THE  WORLD  OF  LIFE 

it  was  carnivorous  (see  Fig.  93).  True  carnivorous  mar- 
supials allied  to  the  ^'  Tasmanian  wolf"  (Thylacinus)  and  the 
Tasmanian  devil  {Sarcopliilus)   are  also  found. 


Fig.  93. —  Skull  of  Thylacoleo  carnifex. 
From  the  Pleistocene  of  Australia.      One-fifth  nat.   size.      (B.M.   Guide.) 


How  and  when  the  marsupials  first  entered  Australia  has 
always  been  a  puzzle  to  biologists,  because  the  only  non-Aus- 
tralian family,  the  opossums,  are  not  closely  allied  to  any  of 
the  Australian  forms,  and  it  is  the  opossums  only  which  have 
been  found  in  tlie  European  early  Tertiaries.  But  recent  dis- 
coveries in  South  America  have  at  length  thrown  some  light 
on  the  question,  since  the  Santa  Cruz  beds  of  Patagonia  (Mid- 
dle Tertiary)  have  produced  several  animals  whose  teeth  so 
closely  resemble  those  of  the  Tasmanian  Thylacinus  that  Mr. 
Lydekker  has  no  doubt  about  their  being  true  marsupials  allied 
to  the  Dasvurid^e.  There  is  also,  in  the  same  beds,  another 
distinct  f amilv  of  small  mammals  —  the  Microbiotheridge  of 
Dr.  Ameghino  —  which,  from  a  careful  study  of  their  denti- 
tion, are  also  considered  by  Mr.  Lydekker  to  be  "  polypro- 
todont  marsupials  of  an  Australian  type."  ^ 

But  even  more  important  is  the  discovery  of  living  mar- 
supials of  the  Australian  rather  than  the  American  type  in  the 
very  heart  of  the  South  American  fauna.  In  1863  a  small 
mouse-like  animal  of  doubtful  affinities  was  captured  in  Ecua- 

lA  Geographical  Historj^  of  Mammals,  p.  109. 


LIFE  OF  TERTIARY  PERIOD  259 

dor.     But  in  1895   a  larger  species  of  the  same  genus  was 
obtained   from   Bogota;    and   it   was   then   seen   that   they   be- 
longed to  a  group  of  which  large  numbers  of  fossil  remains 
had   been  found   in  the   Santa   Cruz   beds.     By   a   comparison 
of  these  remains  of  various  allied   forms  with   the  specimens 
of  those  now  living,  it  seems  no  longer  possible  to  doubt  that 
marsupials  of  Australian  type  have  existed  in  South  America 
in   Middle   or   Late   Tertiary   times,    and   tiiat   some   of   them 
survive  to-day  in  the  equatorial  Andes,  where  their  small  size 
has   probably   saved   them   from   extinction.     Of   these   latter, 
Mr.  Lydekker  says:     "In  the  skeleton  the  lower  jaw  exhibits 
the    usual    inflexion    of    the    angle ;    and    the    pelvis    carries 
marsupial  bones.     A  small  pouch  is  present  in  the  female." 
These   small  marsupials   have   been  named   Csenolestes,   while 
their  fossil  allies  are  so  numerous  and  varied  that  they  have 
to   be    classed    in    three   families  —  Abderitidae,    Epanorthidse, 
and   Garzoniidae.     This   is   only   mentioned  here   to   show   the 
large  quantity  of  materials  upon  which  these  conclusions  are 
founded. 

Teachings  of  Pleistocene  Mammalia 

For  the  purpose  of  the  present  work  it  is  not  necessary  to 
go  into  further  details  as  to  the  development  of  the  higher 
forms  of  life,  except  to  call  attention  to  some  other  cases  of 
the  sudden  dying  out  of  great  numbers  of  the  more  developed 
species  or  groups  during  the  most  recent  geological  period  — 
the  Pleistocene. 

It  has  already  been  shown  how,  in  temperate  South 
America,  the  huge  sloths  and  armadillos,  the  giant  llamas, 
the  strange  Toxodontia,  and  the  early  forms  of  horses  all 
disappeared  at  a  comparatively  recent  epoch.  In  Xorth 
America  a  similar  phenomenon  occurred.  Two  extinct  lions; 
a  number  of  racoons  and  allied  forms,  including  several  ex- 
tinct genera;  six  extinct  species  of  horses;  two  tapirs;  two 
genera  of  peccaries ;  a  llama  and  a  camel ;  several  extinct 
bisons,   sheep,    and   deer;   two   elephants   and   two   mastodons, 


260  THE  WORLD  OF  LIFE 

and  four  genera  of  tlie  wonderful  terrestrial  slotlis,  ranged 
over  the  whole  country  as  far  north  as  Oregon  and  the  Great 
Lakes  in  quite  recent  times;  while  four  genera  of  the  great 
ground-sloths  have  been  found  as  far  north  as  Pennsylvania. 

This  remarkable  assemblage  of  large  Mammalia  at  a  period 
so  recent  as  to  be  coeval  with  that  of  man,  is  most  extraor- 
dinary; while  that  the  whole  series  should  have  disappeared 
before  historical  times  is  considered  by  most  geologists  to  be 
almost  mysterious.  At  an  earlier  period,  especially  during 
the  Miocene  (Middle  Tertiary),  Xorth  America  was  also 
wonderfully  rich  in  Mammalia,  including  not  only  the  ancestors 
of  existing  types,  but  many  now  quite  extinct.  At  this  time 
there  were  several  kinds  of  monkevs  allied  to  South  American 
forms;  numerous  extinct  Carnivora,  including  the  great  sabre- 
toothed  tiger,  Machserodus;  several  ancestral  horses,  includ- 
ing the  European  Anchitherium ;  several  ancestral  rhinoceroses, 
the  huge  horned  Brontotheriidae,  the  Oreodontidse,  and  many 
ancestral  swine.  Almost  all  these  became  extinct  at  the  end 
of  the  Miocene  age.  "^ 

In  Europe  we  find  very  similar  phenomena.  During  the 
Pleistocene  age,  the  great  Irish  elk,  the  cave-lion  and  the 
sabre-toothed  tiger,  cave-bears  and  hyaenas,  rhinoceroses, 
hippopotami  and  elephants,  extinct  species  of  deer,  antelopes, 
sheep  and  cattle,  were  abundant  over  a  large  part  of  Europe 
(many  even  reaching  our  own  country),  and  rapidly  became 
extinct;  and  what  renders  this  more  difficult  to  explain  is, 
that  all  of  these  and  many  others,  with  numerous  ancestral 
forms,  had  inhabited  Europe  throughout  the  Pliocene  and 
some  even  in  Miocene  times. 

These  very  interesting  changes  in  the  northern  hemisphere 
are  paralleled  and  completed  in  far-distant  Australia.  In 
caves  and  surface  deposits  of  recent  formation  a  whole  series 
of  fossil  remains  have  been  found,  all  of  the  marsupial  order, 
and  most  of  them  of  extinct  species  and  even  extinct  genera. 
But  what  is  more  extraordinarv  is,  that  several  of  them  were 
larger  than  any  now  living,  while  some  were  as  gigantic  as 


LIFE  OF  TERTIARY  PERIOD  201 

the  huge  gi'ound-sloths  and  armadillos  of  the  Pampas.  There 
were  numerous  kangaroos,  some  much  lar<Ter  than  any  liv- 
ing,  including  species  allied  to  the  tree-kangaroos  of  New 
Guinea;  a  Phascolomjs  (wombat)  as  large  as  a  donkey;  the 
Diprotodon,  a  thick-limbed  animal  nearly  as  large  as  an 
elephant,  but  allied  both  to  the  kangaroos  and  the  phalangor>. 
Equally  remarkable  was  the  Tliylacoleo  carnifex,  nearly  as 
large  as  a  lion  and  with  remarkable  teeth  (Fig.  03,  p.  258). 
The  very  peculiar  Xototherium,  allied  to  the  wombats,  was 
nearly  as  large  as  a  rhinoceros;  and  several  others  imperfectly 
known  indicate  that  they  were  of  larger  size  than  their  nearest 
living  allies. 

A  number  of  very  similar  facts  are  presented  by  recently 
extinct  birds.  The  Moas  of  ^ew  Zealand  were  of  various 
sizes,  but  the  largest  was  8%  feet  high  when  standing  natu- 
rally, but  when  raising  its  body  and  neck  to  the  fullest  extent 
it  would  have  perhaps  reached  to  a  height  of  12  feet. 

In  Madagascar  also  there  was  a  huge  bird,  the  ^pyornis, 
which  was  probably  larger  than  the  largest  of  the  Moas,  and 
whose  egg,  frequently  found  in  sand-hills,  sometimes  measures 
3  feet  by  2%  feet  in  circumference,  and  will  hold  more  than 
two  gallons.  It  is  almost  certain  that  these  huge  birds  were 
all  coeval  with  early  man,  and  in  the  case  of  the  Moas  this 
has  been  completely  proved  by  finding  their  bones  in  ancient 
native  cooking  ovens.  It  is  probable,  therefore,  that  their 
final  extinction  was  due  to  human  agency. 

Probable   Cause  of  Extinction  of  the  Pleistocejie  Mammalia 

The  complete  extinction  of  many  of  the  largest  Mammalia, 
which  were  abundant  in  almost  all  parts  of  the  world  in 
Pleistocene  times,  has  not  yet  received  a  wholly  satisfactory 
explanation.  The  fact  that  the  phenomenon  is  so  near  to 
our  own  era  renders  it  more  striking  than  similar  occurrences 
in  remote  ages.  With  the  one  exception  of  the  glacial  e]><^ch, 
there  has  been  very  little  modification  of  tlie  earth's  surface 
since  the  close  of  the  Tertiary  era  ;  and  in  several  cases  species 


262  THE  WORLD  OF  LIFE 

which  iindo"abtedly  survived  that  event  have  since  become  ex- 
tinct. This  great  climatic  catastrophe  did  nndoubtedly  pro- 
duce extensive  migration  of  Mammalia ;  but,  owing  to  the  fact 
that  the  ice-sheet  had  very  definite  limits,  and  that  numbers 
of  large  mammals  were  merely  driven  southward,  it  is  not 
held  to  be  a  sufficient  cause  for  so  general  a  destruction  of  the 
larger  forms  of  life. 

Another  circumstance  that  puts  the  glacial  epoch  out  of 
court  as  a  sufficient  explanation  of  the  widespread  extinction 
is  that  in  two  very  remote  parts  of  the  earth,  both  enjoying 
a  warm  or  even  a  sub-tropical  climate  —  x\ustralia  on  the  one 
hand,  and  Brazil  to  Argentina  on  the  other, —  exactly  the 
same  phenomena  have  occurred,  and,  so  far  as  all  the  geo- 
logical evidence  shows,  within  the  same  general  limits  of  time. 

It  is  no  doubt  the  case  that  at  each  of  the  dividing  lines 
of  the  Tertiary  era  —  that  is,  in  passing  from  the  Eocene  to 
the  Miocene,  or  from  the  latter  to  the  Pliocene,  and  thence 
to  the  Pleistocene  —  many  large  Mammalia  have  also  become 
extinct.  But  in  these  cases  a  much  greater  lapse  of  time  can 
be  assumed,  as  well  as  larger  changes  in  the  physical  condi- 
tions, such  as  extension  of  land  or  water,  climate,  vegetation, 
etc.,  which,  combined  with  the  special  disabilities  of  very 
large  animals,  are  sufficient  to  account  for  the  facts.  It  may 
be  well  here  to  state  again  the  causes  which  lead  to  the  ex- 
tinction of  largo  animals  rather  than  small  ones,  as  given 
in  my  Darwinism  (p.  394)  more  than  twenty  years  ago,  and 
also  in  my  Geographical  Distribution  of  Animals,  i.  p.  157 
(1876): 

"  In  the  first  place,  animals  of  great  bulk  require  a  proportionate 
supply  of  food,  and  any  adverse  change  of  conditions  would  affect 
them  more  seriously  than  it  would  affect  smaller  animals.  In  the 
next  place,  the  extreme  specialisation  of  many  of  these  large  animals 
would  render  it  less  easy  for  them  to  become  modified  in  any  new 
direction  required  by  the  changed  conditions.  Still  more  impor- 
tant, perhaps,  is  the  fact  that  very  large  animals  always  increase 
slowly  as  compared  with  small  ones  —  the  elephant  producing  a 


LIFE  OF  TERTIARY  PERIOD  203 

single  young  one  every  three  years,  while  a  rahbit  may  have  a  litter 
of  seven  or  eight  young  two  or  three  times  a  year.  Now  the  prob- 
ability of  useful  variations  will  be  in  direct  proportion  to  the  popu- 
lation of  the  species,  and,  as  the  smaller  animals  are  not  only  many 
hundred  times  more  numerous  than  the  largest,  but  also  increase 
perhaps  a  hundred  times  as  rapidly,  they  are  able  to  become  quickly 
modified  by  variation  and  natural  selection,  while  the  large  and 
bulky  species,  being  unable  to  vary  quickly  enough,  are  obliged  to 
succumb  in  the  struggle  for  existence/^ 

To  these  reasons  we  may  add  that  very  large  animals  arc 
less  rapid  in  their  motions,  and  thus  less  able  to  escape  from 
enemies  or  from  many  kinds  of  danger.  The  late  Professor 
O.  Marsh,  of  Yale  University,  has  well  observed : 

"  In  every  vigorous  primitive  type  which  was  destined  to  survive 
many  geological  changes,  there  seems  to  have  been  a  tendency  to 
throw  off  lateral  branches,  which  became  highly  specialised,  and 
soon  died  out  because  they  were  unable  to  adapt  themselves  to  new 
conditions.  .  .  .  The  whole  narrow  path  of  the  Suilline  (hog) 
type,  throughout  the  entire  series  of  the  American  tertiaries,  is 
strewn  w4th  the  remains  of  such  ambitious  offshoots,  manv  of  them 
attaining  the  size  of  a  rhinoceros;  while  the  typical  pig,  with  an 
obstinacy  never  lost,  has  held  on  in  spite  of  catastrophes  and  evolu- 
tion, and  still  lives  in  America  to-day." 

We  may  also  remember  that  it  is  still  more  widely  spread 
over  the  Old  World,  under  the  various  forms  of  the  hojr-family 
(Suidse),  than  it  is  in  America,  under  the  closely  allied 
peccary  type  (Dicotylida?). 

That  this  is  a  true  cause  of  the  more  frequent  passing  away 
of  the  largest  animal  types  in  all  geological  epochs  there  can 
be  no  doubt,  but  it  certainly  will  not  alone  explain  the  dying 
out  of  so  many  of  the  very  largest  ^Mammalia  and  birds  dur- 
ing a  period  of  such  limited  duration  as  is  the  Pleistocene 
(or  Quaternary)  age,  and  under  conditions  which  were  cer- 
tainly not  very  different  from  those  under  whicli  they  had 
been  developed  and  had  lived  in  many  cases  down  to  the 
historical  period. 


264  THE  WORLD  OF  LIFE 

What  we  are  seeking  for  is  a  cause  which  has  been  in 
action  over  the  whole  earth  during  the  period  in  question, 
and  which  was  adequate  to  produce  the  observed  result. 
AVhen  the  problem  is  stated  in  this  way  the  answer  is  very 
obvious.  It  is,  moreover,  a  solution  which  has  often  been 
suggested,  though  generally  to  be  rejected  as  inadequate.  It 
has  been  so  with  myself,  but  why  I  can  hardly  say.  In  his 
Antiquity  of  Man  (4th  ed.,  1873,  p.  418)  Sir  Charles  Lyell 
says: 

^^  That  the  growing  power  of  man  may  have  lent  its  aid  as  the 
destroying  cause  of  many  Pleistocene  species  must,  however,  be 
granted;  yet,  before  the  introduction  of  fire-arms,  or  even  the  use 
of  improved  weapons  of  stone,  it  seems  more  wonderful  that  the 
aborigines  were  able  to  hold  their  own  against  the  cave-lion,  hyena, 
and  wild  bull,  and  to  cope  with  such  enemies,  than  that  they  failed 
to  bring  about  their  extinction.'' 

Looking  at  the  whole  subject  again,  with  the  much  larger 
bodv  of  facts  at  our  command,  I  am  convinced  that  the  above 
somewhat  enigmatic  passage  really  gives  the  clue  to  the  whole 
problem,  and  that  the  rapidity  of  the  extinction  of  so  many 
large  Mammalia  is  actually  due  to  man's  agency,  acting  in 
co-operation  with  those  general  causes  w^hich  at  the  culmina- 
tion of  each  geological  era  has  led  to  the  extinction  of  the 
larger,  the  most  specialised,  or  the  most  strangely  modified 
forms.  The  reason  why  this  has  not  been  seen  to  be  a  suffi- 
cient explanation  of  the  phenomena  is,  I  think,  due  to  two 
circumstances.  Even  since  the  fact  of  the  antiquity  of  man 
w^as  first  accepted  by  European  geologists  only  half  a  century 
ago,  each  fresh  discovery  tending  to  extend  that  antiquity  has 
been  met  with  the  same  incredulity  and  opposition  as  did 
the  first  discovery  of  flint  weapons  by  Boucher  de  Perthes 
in  the  gTavels  near  Amiens.  It  has  been  thought  necessary 
to  minimise  each  fresh  item  of  evidence,  or  in  many  cases  to  re- 
ject it  altogether,  on  the  plea  of  imperfect  observation.  Thus 
the  full  weight  of  the  ever-accumulating  facts  has  never  been 


LIFE  OF  TERTIAKY  TERIOD  265 

adequately  recognised,  because  each  new  writer  has  Weu  afraid 
to  incur  the  stigma  of  credulity,  and  therefore  usually  limited 
himself  to  such  facts  as  he  had  himself  observed,  or  could  quote 
from  his  best-known  contemporaries.  On  the  other  hand,  the 
old  idea  that  man  was  the  latest  product  of  nature  (or  of 
evolution)  still  makes  itself  felt  in  the  attempt  to  escape  from 
any  evidence  proving  man's  coexistence  with  such  extinct 
species  as  would  imply  greater  antiquity.  In  the  chapter  on 
The  Antiquity  of  Man  in  l^orth  America  (in  my  Xatural 
Selection  and  Tropical  !N'ature)  I  have  given  numerous  ex- 
amples of  both  these  states  of  mind.  And  what  makes  them 
so  specially  unreasonable  is,  that  all  evolutionists  are  satis- 
fied that  the  common  ancestor  of  man  and  the  anthropoid  apes 
must  date  back  to  the  Miocene,  if  not  to  the  Eocene  period ; 
so  that  the  real  mystery  is,  not  that  the  works  or  the  remains 
of  ancestral  man  are  found  throughout  the  Pleistocene  period, 
but  that  they  are  not  also  found  throughout  the  Pliocene,  and 
also  in  some  Miocene  deposits.  There  is  not,  as  often  as- 
sumed, one  "  missing  link "  to  be  discovered,  but  at  least  a 
score  such  links,  adequately  to  fill  the  gap  between  man  and 
apes ;  and  their  non-discovery  is  now^  one  of  the  strongest 
proofs  of  the  imperfection  of  the  geological  record. 

When  we  find,  as  we  do,  that,  with  the  one  exception  of 
Australia,  proofs  of  man's  coexistence  with  all  the  great  ex- 
tinct Pleistocene  Mammalia  are  sufiiciently  clear,  while  that 
the  Australians  are  equally  ancient  is  proved  by  their  form- 
ing so  well-marked  and  unique  a  race,  the  fact  that  man  should 
every^vhere  have  helped  to  exterminate  the  various  hugo 
quadrupeds,  whose  flesh  would  be  a  highly  valued  food,  al- 
most becomes  a  certainty.  The  following  passage  from  one 
of  our  best  authorities,  Mr.  R.  Lydekker,  F.K.S.,  puts  the 
w^hole  case  in  a  very  clear  light,  though  he  does  not  definitely 
accept  the  conclusion  whicli  I  hold  to  be  now  well  established. 
He  says: 

"  From  the  northern  half  of  the  Old  World  have  disappeared  the 
mammoth,  the  elasmothere  (a  very  peculiar,  huge  rhinoceros,  whose 


266  THE  WORLD  OP  LIFE 

skull  was  more  than  three  feet  long),  the  woolly  and  other  rhino- 
ceroses, the  sabre-toothed  tigers,  etc.;  North  America  has  lost  the 
megalonyx  and  the  Ohio  mastodon;  from  South  America,  the 
glyptodonts,  mylodons,  the  megalothere,  and  the  macrauchenia 
have  been  swept  away;  while  Australia  no  longer  possesses  the 
diprotodon  and  various  gigantic  species  of  kangaroos  and  wombats. 
In  the  northern  hemisphere  this  impoverishment  of  the  fauna  has 
been  very  generally  attributed  to  the  effects  of  the  glacial  period, 
but,  although  this  may  have  been  a  partial  cause,  it  can  hardly  be 
the  only  one.  The  mammoth,  for  instance,  certainly  lived  during 
a  considerable  portion  of  the  glacial  epoch,  and  if  it  survived  thus 
far,  why  should  it  disappear  at  the  close?  Moreover,  all  the  Eu- 
ropean mastodons  and  the  southern  elephant  {Elephas  meridionalis) 
died  out  before  the  incoming  of  glacial  conditions;  and  the  same 
is  true  of  all  the  extinct  elephants  and  mastodons  of  Southern 
Asia.  Further,  a  large  number  of  English  geologists  believe  the 
brick  earths  of  the  Thames  valley,  which  contain  remains  of  rhino- 
ceroses and  elephants  in  abundance,  to  be  of  post-glacial  age.  As 
regards  the  southern  hemisphere,  it  can  hardly  be  contended  that 
glacial  conditions  prevailed  there  at  the  same  time  as  in  the  north- 
ern half  of  the  world. 

"  It  is  thus  evident  that,  though  a  very  great  number  of  large 
mammals  were  exterminated  (perhaps  partly  by  the  aid  of  human 
agency)  at  the  close  of  the  Pleistocene  period,  when  the  group  had 
attained  its  maximum  development  as  regards  the  bodily  size  of  its 
members,  yet  other  large  forms  had  been  steadily  dying  out  in 
previous  epochs.  And  it  would  seem  that  there  must  be  some 
general,  deep-seated  cause  affecting  the  life  of  a  species  with  which 
we  are  at  present  unacquainted.  Indeed,  as  there  is  a  term  to  the 
life  of  an  individual,  what  is  more  natural  than  that  there  should 
also  be  one  to  the  existence  of  a  species.  It  still  remains  indeed, 
to  account  for  the  fact  that  the  larger  Pleistocene  mammals  had 
no  successors  in  the  greater  part  of  the  world,  but  perhaps,  is  in 
some  way  connected  with  the  advent  of  man."  ^ 

It  is  sometimes  thought  that  early  man,  with  onlv  the  rudest 
weapons,   would   be   powerless    against   large    and   often   well- 

1  A  Geographical  History  of  Mammals,  R.  Lydekker,  B.A.,  F.R.S.,  V.P.G.S. 
etc.,  1896,  p.  18. 


LIFE  OF  TEKTIAEY  PERIOD  267 

armed  mammals.  But  this,  I  think,  is  quite  a  mistake.  Xo 
weapon  is  more  effective  for  this  purpose  than  a  spear,  of 
various  kinds,  when  large  numbers  of  hunters  attack  a  single 
animal;  and  when  made  of  tough  wood,  with  the  point  hard- 
ened by  fire  and  well  sharpened,  it  is  as  effective  as  when 
metal  heads  are  used.  Bamboo,  too,  abundant  in  almost  all 
warm  countries,  forms  a  very  deadly  spear  when  cut  obliquely 
at  the  point.  The  way  in  which  even  a  man-eating  tiger  is 
killed  by  this  means  in  Java  is  described  in  my  ^lalay 
Archipelago  (p.  82).  Such  a  method  would  doubtless  have 
been  adopted  even  by  Palaeolithic  man,  and  would  have  been 
effective  against  any  of  the  larger  animals  of  the  Pleistocene 
age. 

It  is  therefore  certain,  that,  so  soon  as  man  possessed 
weapons  and  the  use  of  fire,  his  power  of  intelligent  com- 
bination would  have  rendered  him  fully  able  to  kill  or  cap- 
ture any  animal  that  has  ever  lived  upon  the  earth ;  and  as 
the  flesh,  bones,  hair,  horns,  or  skins  would  have  been  of 
use  to  him,  he  would  certainly  have  done  so  even  had  he 
not  the  additional  incentive  that  in  many  cases  the  animals 
were  destructive  to  his  crops  or  dangerous  to  his  children  or 
to  himself.  The  numbers  he  would  be  able  to  destroy,  es- 
pecially of  the  young,  would  be  an  important  factor  in  the 
extermination  of  many  of  the  larger  species. 

There  remains,  however,  the  question,  well  put  by  Mr. 
Lydekker,  whether  there  is  not  some  general  deep-seated  cause 
affecting  the  life  of  species,  and  sending  to  explain,  if  only 
partially,  the  successive  dying  out  of  numbers  of  large  ani- 
mals involving  a  complete  change  in  the  preponderant  typos 
of  organic  life  at  certain  epochs;  and  to  this  question  and 
some  others  allied  to  it  a  separate  chapter  must  be  devoted. 

APPEXDIX 

THE  THEORY    OF    COXTINEXTAL   EXTEXSIOXS 

Most  writers  consider  that  the  preceding  facts  (see  p.  2-11)  go  to 
prove  the  existence  of  a  land-connection  l)otwecn  Soiitli   America 


268  THE  WORLD  OF  LIFE 

and  Australia  in  Early  or  Middle  Tertiary  times.  This,  however, 
seems  to  me  to  be  highly  improbable  for  reasons  given  at  full  in  my 
Island  Life.  Its  supposed  necessity  depends  on  the  assumption 
that  the  geological  record  is  fairly  complete,  even  as  regards  these 
small  mammals,  and  that  their  not  being  yet  discovered  in  the 
northern  continents  proves  that  they  never  existed  there.  But  the 
extreme  rarity  of  the  small  Secondary  Mammalia,  though  they  have 
been  found  scattered  over  the  whole  northern  hemisphere,  and  the 
limited  area  in  South  America  in  which  these  Tertiary  marsupials 
have  been  found,  taken  in  connection  with  the  enormous  areas  of 
geologically  unexplored  land  in  Asia  and  Australia,  should  make  us 
very  cautious  in  assuming  such  vast  and  physically  improbable 
changes  of  land  and  sea  at  such  a  comparatively  recent  epoch. 
The  theory  of  land-connection  also  introduces  enormous  difficulties 
of  various  kinds  which  it  is  well  briefly  to  consider.  If  we  suppose 
an  absolute  land-connection  in  order  to  allow  the  marsupial  type  to 
have  entered  Australia  from  temperate  South  America,  we  have 
to  face  the  incredible  fact,  that  of  the  whole  varied  mammalian 
fauna  of  the  latter  country  this  one  group  only  was  transmitted. 
In  these  same  deposits  there  are  found  ancestral  hoofed  animals  of 
small  size  (Pyrotherium)  ;  numerous  rodents  allied  to  cavies  and 
porcupines;  a  host  of  Edentata  allied  to  sloths,  ant-eaters,  and 
armadillos.  These,  taken  altogether,  are  many  times  more  numer- 
ous than  the  marsupials;  they  were  more  varied  in  structure  and 
mode  of  life;  and  it  is  almost  incredible  that  not  one  representa- 
tive of  these  somewhat  higher  forms  sliould  have  reached  the  new 
country,  or  having  reached  it  should  have  all  died  out,  while  the 
inferior  group  alone  survived.  Then,  again,  we  know  that  birds 
and  insects  must  have  abounded  in  South  America  at  the  same 
period,  while  the  whole  7000  miles  of  connecting  land  must  have 
been  well  clothed  with  vegetation  to  support  the  varied  life  that 
must  have  existed  upon  it  during  the  period  of  immigration.  Yet 
no  indication  of  a  direct  transference  or  interchange  of  these  nu- 
merous forms  of  life  in  any  adequate  amount  is  found  in  either 
Australia  or  South  Temperate  America.  We  can  hardly  suppose 
such  an  enormous  extent  of  land  to  have  been  raised  above  the 
ocean;  that  it  should  have  become  sufficiently  stocked  with  life  to 
serve  as  a  bridge  (7000  miles  long!),  and  that  a  few  very  small 
marsupials  only  should  have  crossed  it;  that  it  then  sank  as  rap- 


LIFE  OF  TERTIARY  PERIOD  261) 

idly  as  it  had  been  formed;  with  the  one  result  of  slocking  Aus- 
tralia with  marsupials,  while  its  other  forms  of  life  —  plants,  birds, 
insects,  molluscs  —  show  an  unmistakable  derivation  from  the 
Asiatic  continent  and  islands.  A  careful  examination  ol'  a  large 
globe  or  South  Polar  map,  with  a  consideration  of  the  diagram  of 
the  proportionate  height  of  land  and  depth  of  ocean  at  p.  .315  of 
my  Darwinism,  together  with  the  argument  founded  upon  it,  will, 
I  think,  convince  my  readers  that  difficulties  in  geographical  dis- 
tribution cannot  be  satisfactorily  explained  by  such  wildly  im- 
probable hypotheses.  If  the  facts  are  carefully  examined,  it  will 
be  found,  as  I  have  shown  for  the  supposed  "  Atlantis "  and 
"  Lemuria,"  that  such  hypothetical  changes  of  sea  and  land  always 
create  more  serious  difficulties  than  those  which  they  are  supposed 
to  explain.  People  never  seem  to  consider  what  such  an  explana- 
tion really  means.  They  never  follow  out  in  imagination,  step  by 
step,  the  formation  of  any  such  enormous  connecting  lands  between 
existing  continents  in  accordance  with  what  we  know  of  the  rate 
of  elevation  and  depression  of  land,  and  the  corresponding  organic 
changes  that  must  ensue.  They  seem  to  forget  that  such  a  vast 
and  complete  change  of  position  of  sea  and  land  is  not  really  known 
ever  to  have  occurred. 

Let  us  consider  for  a  moment  what  the  supposed  land-connection 
between  South  America  and  Australia  really  implies.  The  distance 
is  more  than  half  as  much  again  as  the  whole  length  of  the  South 
American  continent,  and  1000  miles  farther  than  from  Southamj)- 
ton  to  the  Cape.  This  alone  should  surely  give  us  pause.  P)ut 
unless  we  go  as  far  south  as  the  Antarctic  circle,  the  depth  of  the 
intervening  ocean  is  about  two  miles;  and  until  we  get  near  Xew 
Zealand  there  is  not  a  single  intervening  island.  There  are  here 
none  of  the  indications  we  expect  to  find  of  any  geologically  recent 
depression  of  land  on  a  vast  scale.  Of  course  we  may  suppose  the 
connection  to  have  been  along  a  great  circle  within  ten  degrees  of 
the  South  Pole,  but  that  will  not  greatly  shorten  the  distance, 
while  we  have  not  a  particle  of  evidence  for  such  a  vast  ehange  of 
climate  in  Mid-Tertiary  times  as  w(nild  be  required  to  render  such 
a  route  possible.  But  the  mere  physical  dilhculties  are  equally 
great.  All  land  elevation  or  depression  of  which  we  have  geo- 
logical evidence  has  been  exceedingly  gradual,  very  limited  in 
extent,  and  always  balanced  by  adjacent  opposite  movements.     Such 


270  THE  WORLD  OF  LIFE 

movements  appear  to  be  slow  creeping  undulations  passing  over 
continental  plateaus  and  their  immediately  adjacent  submarine 
extensions.  Sometimes  the  depressions  seem  to  have  taken  the 
form  of  basins;  but  we  cannot  conceive  of  any  elevation  of  conti- 
nental dimensions,  or  depression  of  oceanic  character  as  to  depth 
and  area,  without  the  complementary  movement  to  complete  the  un- 
dulation. A  continental  extension  between  South  America  and 
Australia  would  almost  necessarily  imply  a  subsidence  of  one  or 
both  of  those  countries  over  an  equal  area  and  to  an  equal  depth; 
and,  so  far  as  I  am  aware,  no  geological  evidence  has  been  ad- 
duced of  any  such  vast  changes  having  occurred  at  so  recent  a 
period  in  either  continent.  I  believe  it  can  now  be  truly  said  that 
no  stratigraphical  geologist  accepts  the  theory  of  frequent  inter- 
changes of  continental  and  oceanic  areas,  which  are  so  hastily 
claimed  by  palaeontologists  and  biologists  to  be  necessary  in  order 
to  overcome  each  apparent  difficulty  in  the  distribution  of  living 
or  extinct  organisms,  and  this  notwithstanding  the  number  of  such 
difficulties  which  later  discoveries  have  shown  to  be  non-existent. 


CHAPTER  XIII 

SOME   EXTENSIONS   OF  DARWIn's   THEORY 

During  the  fifty  years  that  have  elapsed  since  the  Darwinian 
theory  was  first  adequately,  though  not  exhaustively,  set  fortli, 
it  has  been  subject  to  more  than  the  usual  amount  of  ob- 
jection and  misapprehension  both  by  ignorant  and  learned 
critics,  by  old-fashioned  field-naturalists,  and  by  the  newer 
schools  of  physiological  specialists.  Most  of  these  objections 
have  been  shown  to  be  fallacious  by  some  of  the  most  eminent 
students  of  evolution  both  here  and  on  the  Continent;  but 
a  few  still  remain  as  stumbling-blocks  to  many  earnest  readers, 
and,  as  they  are  continually  adduced  as  being  serious  difii- 
culties  to  the  acceptance  of  natural  selection  as  a  sufficient  ex- 
planation of  the  origin  of  species,  I  propose  to  give  a  short 
statement  of  what  seem  to  me  the  three  objections  that  most 
require  an  answer  at  the  present  time.  They  are  the  follow- 
ing:— 

1.  How  can  the  beginnings  of  new  organs  be  explained  ? 

2.  How  can  the  exact  co-ordination  of  variations,  needed 
to  produce  any  beneficial  result,  be  effected  with  sufficient 
rapidity  and  certainty  ? 

3.  How  is  it  that  excessive  developments  of  bulk,  weapons, 
ornaments,  or  colours,  far  beyond  any  utilitarian  requirements, 
have  been  so  frequently  produced  ? 

These  three  objections  are  of  increasing  degrees  of  impor- 
tance. The  first  is,  in  my  opinion,  wholly  speculative  and 
of  no  value,  inasmuch  as  it  applies  to  wliat  happened  in  the 
earlier  stages  of  evolution,  of  which  we  have  a  mininium 
of  knowledge.  The  second  is  of  somrwliat  more  importance: 
for,  though  in  the  great  majority  of  cases  of  adaptation  the 
ordinarv   well-known    facts    of   variation    and    survival    would 

271 


272  THE  WORLD  OF  LIFE 

amply  suffice,  yet  there  are  conceivable  cases  in  wbich  they 
might  be  insufficient,  and  these  cases  are  now  explained  by 
a  very  interesting  combination  of  the  effects  of  acquired 
modifications  of  the  individual  with  the  selection  of  congenital 
variations.  The  third  is,  I  think,  somewhat  more  important, 
as  indicating  a  real  deficiency  in  the  theory,  as  originally 
stated,  but  which  is  now  well  supplied  by  an  extension  of 
that  theory  from  the  body  itself  to  the  reproductive  germs 
from  which  its  parts  are  developed.  I  will,  therefore,  en- 
deavour to  explain  in  as  simple  a  manner  as  possible  how 
these  three  objections  have  been  overcome. 

(1)   The  Beginnings  of  Organs 

The  objection  that  the  first  slight  beginnings  of  new  organs 
would  be  useless,  and  that  they  could  not  be  preserved  and 
increased  by  natural  selection,  was  one  of  the  most  frequent 
in  the  early  stages  of  the  discussion  of  the  theory,  and  was 
answered  by  Darwin  himself  in  the  later  editions  of  his  book. 
But  the  objection  still  continues  to  be  made,  and  owing  to 
the  great  mass  of  controversial  literature  continually  issued 
from  the  press  many  of  the  objectors  do  not  see  the  replies 
made  to  them ;  there  is  therefore  still  room  for  a  somewhat 
more  general  answer,  wdiich  will  apply  not  only  to  certain 
individual  cases,  but  to  all.  The  most  general  and  therefore 
the  best  answ^er  I  have  yet  seen  given  is  that  of  Professor 
E.  B.  Poulton  in  his  recently  published  Essays  on  Evolution. 
He  says: 

"  Organs  are  rarely  formed  anew  in  an  animal,  but  they  are 
formed  by  the  modification  of  pre-existing  organs ;  so  that,  instead 
of  having  one  beginning  for  each  organ,  we  have  to  push  the  be- 
ginning further  and  further  back,  and  find  that  a  single  origin  ac- 
counts for  several  successive  organs,  or  at  any  rate  several  functions, 
instead  of  one." 

He  then  goes  on  to  show  that  the  four  limbs  of  vertebrates 
have  been  again  and  again  modified,  for  running,  for  climbing 


to? 


EXTEXSIOXS  OF  DARWINISM  273 

for  burrowing,  for  swimming,  or  for  flying,  and  that  their 
first  appearance  goes  back  to  PalaBozoic  times  in  the  paired 
fins  of  early  fishes,  while  their  actual  or'ujiii  must  have  been 
much  further  back,  in  creatures  whose  skeleton  was  not  suffi- 
ciently solidified  to  be  preserved. 

There  is,  however,  a  more  general  explanation  even  than 
this,  and  one  that  applies  to  what  has  always  been  hehl  to 
be  the  most  difiicult  of  all  —  that  of  the  origin  of  the  organs 
of  sense. 

The  various  sensations  by  which  w^e  come  into  relation  with 
the  external  world  —  sight,  hearing,  smell,  taste,  and  touch 
■ —  are  really  all  specialisations  of  the  last  and  most  general, 
that  of  material  contact.  We  hear  by  means  of  a  certain 
range  of  air-waves  acting  on  a  specially  constructed  vibrating 
organ ;  we  smell  by  the  contact  of  excessively  minute  particles, 
or  actual  molecules,  given  off  by  certain  substances ;  we  taste 
by  the  action  of  soluble  matter  in  food  on  the  papilke  of  the 
tongue;  and  we  see  by  the  impact  of  ether-vibrations  on  the 
retina;  and  as  other  ether-vibrations  produce  sensations  of 
cold  or  warmth,  or,  when  in  excess,  acute  pain,  in  every  part 
of  the  body,  the  modern  view,  that  matter  and  ether  are  funda- 
mentally connected  if  not  identical,  seems  not  unreasonable. 

Xow,  as  all  our  organs  of  sense,  however  complex,  are  built 
up  from  the  protoplasm  which  constitutes  the  material  of  all 
living  organisms,  and  as  all  animals,  however  simple,  exhibit 
reactions  which  seem  to  imply  that  they  have  the  rudiments 
of  most,  if  not  all  of  our  senses,  we  may  conclude  that  just 
in  proportion  as  they  have  advanced  in  complexity  of  organi- 
sation, so  have  special  parts  of  their  bodies  become  adapted 
to  receive,  and  their  nervous  system  to  respond  to,  tlio  varinn? 
contacts  with  the  outer  world  which  produce  what  wo  terra 
sensations.  There  is  therefore,  probably,  no  point  in  the 
whole  enormous  length  of  the  cliain  of  being,  fnnn  ourselves 
back  to  the  simple  one-celled  Amoeba,  iu  which  the  rudiments 
of  our  five  senses  did  not  exist,  although  no  separnto  organs 
may  be   detected.     Just   as  its   whole  body   sen'os   alternately 


274  THE  WORLD  OF  LIFE 

as  outside  or  inside,  as  skin  or  as  stomach,  as  limbs  or  as 
lips,  so  may  every  part  of  it  receive  a  slightly  different  sensa- 
tion from  a  touch  outside  or  a  touch  inside,  from  an  air- 
vibration  or  from  an  ether-vibration,  from  those  emanations 
which  effect  us  as  noxious  odours  or  disgusting  tastes.  But 
if  this  view  is  a  sound  one,  as  I  think  it  will  be  admitted 
that  it  is,  how  absurd  is  it  to  ask,  "  How  did  the  eye  or  the 
ear  begin  ? "  They  began  in  the  potentiality  of  that  marvel- 
lous substance,  protoplasm,  and  they  were  rendered  possible 
when  that  substance  was  endowed  with  the  mysterious  or- 
ganising power  we  term  life.  First  the  cell  was  produced; 
and,  from  the  continued  subdivision  of  the  cell  at  each  sub- 
division taking  a  slightly  different  form  and  function,  numer- 
ous one-celled  animals  were  formed;  and  a  little  later  the 
union  of  many  cells  of  diverse  forms  and  functions  led  to  the 
endless  multicellular  creatures,  constituting  the  entire  world  of 
life. 

Thus  every  substance  and  every  organ  came  into  existence 
when  required  by  the  organism  imder  the  law  of  perpetual 
variation   and   survival   of   the   fittest,    only    limited   by   the 
potentialities  of  living  protoplasm.     And  if  the  higher  sense- 
organs  were  so  produced,  how  much  easier  was  the  production 
of  such  superficial  appendages  as  horns  and  tusks,  scales  and 
feathers,    as   they   were    required.     Horns,    for    instance,    are 
either  dermal  or  osseous  outgrowths  or  a  combination  of  both. 
In   the    very    earliest   known    vertebrates,    the    fishes    of    the 
Silurian  formation,  we  find  the  skin  more  or  less  covered  with 
tubercles,  or  plates,  or  spines.     Here  we  have  the  rudiments 
of  all  those  dermal  or  osseous  outgrowths  which  continue  in 
endless    modifications    through   the    countless    ages    that    have 
elapsed  down  to  our  own  times.     They  appear  and  disappear, 
as  they  are  useful  or  useless,  on  various  parts  of  the  body, 
as  that  body  changes  in  form  and  in  structure,   and  modifi- 
cations of  its  external  covering  are  needed.     Hence  the   in- 
finite  variety   in   nature  —  a   variety   which,   were   it  not   so 
familiar,  would  be  beyond  the  wildest  flights  of  imagination 


EXTENSIONS  OF  DARWINISM  275 

to  suggest  as  possible  developments  from  an  apparently  simple 
protoplasmic  cell.  The  idea,  therefore,  that  there  were,  or 
could  be,  at  any  successive  periods,  anything  of  the  nature  of 
the  abrupt  beginning  of  completely  new  organs  which  had 
nothing  analogous  in  preceding  generations  is  quite  unsup- 
ported by  what  is  known  of  the  progressive  development  of 
all  structures  through  slight  modification  of  those  which  pre- 
ceded them.  The  objection  as  to  the  heglmiings  of  new  organs 
is  a  purely  imaginary  one,  wdiich  entirely  falls  to  pieces  in 
view  of  the  wdiole  known  process  of  development  from  the 
simplest  cell  (though  in  reality  no  cell  is  simple)  to  ever 
higher  and  more  complex  aggregations  of  cells,  till  we  come 
to  Mammalia  and  to  man. 

(2)   The  Co-ordination  of  Variations 

The  next  difficulty,  one  which  Herbert  Spencer  laid  much 
stress  on,  is,  that  every  variation,  to  be  of  any  use  to  a  species, 
requires  a  number  of  concurrent  variations,  often  in  dilTerent 
parts  of  the  body,  and  these,  it  is  said,  cannot  be  left  to 
chance.  Herbert  Spencer  discussed  this  poi';t  at  great  length 
in  his  Factors  of  Organic  Evolution ;  and,  as  one  of  the  illus- 
trative cases,  he  takes  the  giraffe,  w^hose  enormously  long  neck 
and  fore-legs,  he  thinks,  would  have  required  so  many  con- 
current variations  that  we  cannot  suppose  them  to  have  oc- 
curred through  ordinary  variation.  He  therefore  argues  that 
the  inherited  effects  of  use  and  disuse  are  the  onlv  causes 
which  could  have  brought  it  about;  and  Darwin  himself  ap- 
pears to  have  thought  that  such  inheritance  did  actually  occur. 

The  points  which  Spencer  mainly  dwells  upon  are  as  fol- 
lows :  The  increased  length  and  massiveness  of  the  neck 
would  require  increased  size  and  strength  of  the  chest  with 
its  bones  and  muscles  to  bear  the  additional  weight,  and  also 
great  additions  to  the  strength  of  the  fore-legs  to  carry  such 
a  burthen.  Again,  as  the  hind-legs  have  remained  short,  the 
whole  body  is  at  a  different  angle  from  what  it  was  before 
the  change   from   the  ordinary   antelope-type,   and   this   would 


276  THE  WORLD  OE  LIFE 

require  a  different  shape  in  the  articulating  joints  of  the  hips 
and  some  change  in  the  muscles;  and  this  would  be  the  more 
important  as  the  hind-  and  fore-legs  now  have  unequal  angular 
motions  when  galloping,  involving  changed  co-ordination  in 
all  the  connected  parts,  any  failure  in  which  would  diminish 
speed  and  thus  be  fatal  to  the  varying  individuals.  Even 
the  blood-vessels  and  nerves  of  these  various  parts  would  re- 
quire modifioations  exactly  adapted  to  the  change  in  the  other 
parts ;  and  he  urges  that  any  individuals  in  Avhich  all  these 
necessary  variations  did  not  take  place  simultaneously,  would 
be  at  a  disadvantage  and  would  not  survive.  To  do  his  argu- 
ment justice,  I  will  quote  one  of  his  most  forcible  paragraphs. 

"  The  immense  change  in  the  ratio  of  fore-quarters  to  hind- 
quarters would  make  requisite  a  corresponding  change  of  ratio  in 
the  appliances  carr3dng  on  the  nutrition  of  the  two.  The  entire 
vascular  system,  arterial  and  venous,  would  have  to  undergo  succes- 
sive unbuildings  and  rebuildings  to  make  its  channels  everywhere 
adequate  to  the  local  requirements,  since  any  want  of  adjustment 
in  the  blood-supply  to  this  or  that  set  of  muscles  would  entail  in- 
capacity, failure  of  speed,  and  loss  of  life.  Moreover,  the  nerves 
supplying  the  various  sets  of  muscles  would  have  to  be  appropriately 
changed,  as  well  as  the  central  nervous  tracts  from  which  they 
issued.  Can  we  suppose  that  all  these  appropriate  changes,  too, 
would  be,  step  by  step,  simultaneously  made  by  fortunate  spon- 
taneous variations  occurring  along  with  all  the  other  fortunate 
spontaneous  variations?  Considering  how  immense  must  be  the 
number  of  these  required  changes,  added  to  the  changes  above 
enumerated,  the  chances  against  any  adequate  readjustments  for- 
tuitously arising  must  be  infinity  to  one." 

Xow,  this  seems  very  forcible,  and  has,  no  doubt,  con- 
vinced many  readers.  Yet  the  argument  is  entirely  fallacious, 
because  it  is  founded  on  the  tacit  assumption  that  the  number 
of  the  varying  individuals  is  very  small,  and  that  the  amount 
of  coincident  variation  is  also  both  small  and  rare.  It  is 
further  founded  on  the  assumption  that  the  time  allowed  for 
the  production  of  any  sufficient  change  to  be  of  use  is  also 


EXTEIsTSIONS  OF  DARWINISM  277 

small.  But  I  have  shown  in  the  early  chapters  of  this  book 
(and  much  more  fully  in  my  Darwinism)  that  all  these  as- 
sumptions are  the  very  reverse  of  the  known  facts.  The 
numbers  of  varying  individuals  in  any  dominant  species  (and 
it  is  only  these  which  become  modified  into  new  species)  is 
to  be  counted  by  millions ;  and  as  the  whole  number  can,  as 
regards  any  needed  modification,  be  divided  into  two  lialves 
—  those  which  possess  the  special  quality  required  above  or 
below  the  average  —  it  may  be  said  thali  nearly  half  the  total 
number  vary  favourably,  and  about  one-fourth  of  the  whole 
number  in  a  very  large  degree.  Again,  it  has  been  shown 
that  the  number  of  coincident  variations  are  very  great,  since 
they  are  always  present  when  only  a  dozen  or  twenty  individ- 
uals are  compared;  bnt  nature  deals  with  thousands  and  mil- 
lions of  individuals.  Yet,  again,  we  know  that  changes  of  the 
environment  are  always  very  slow  as  measured  by  years  or 
generations,  since  not  a  single  new  species  is  known  to  have 
come  into  existence  during  the  whole  of  the  Pleistocene  period ; 
and  as  fresh  variations  occur  in  every  generation,  almost  any 
character,  with  all  its  co-ordinated  structures,  would  be  con- 
siderably modified  in  a  hundred  or  a  thousand  generations,  and 
■we  have  no  absolute  knowledge  that  any  great  change  would 
be  required  in  less  time  than  this.^ 

lA  very  familiar  fact  will,  I  think,  show  that  a  large  amount  of  co- 
ordinated variability  in  different  directions  does  actually  occur.  First-rate 
bowlers  and  wicket-keepers,  as  well  as  first-rate  batters,  are  not  common  in 
proportion  to  the  whole  population  of  cricket-players.  Each  one  of  these 
requires  a  special  set  of  co-ordinated  faculties  —  good  eyesight,  accurate 
\  perception  of  distance  and  of  time,  with  extremely  rapid  and  accurate  re- 
sponse of  all  the  muscles  concerned  in  the  operations  each  has  to  perform. 
If  all  the  special  variations  required  to  produce  such  individuals  were  sot 
forth  by  a  good  physiologist  in  the  detailed  and  forcible  manner  of  the 
passage  quoted  from  Spencer  about  the  giraffe,  it  would  seem  impossible 
that  good  cricketers  should  ever  arise  from  the  average  family  types.  Yat 
they  certainly  do  so  arise.  And  just  as  cricketers  are  chosen,  not  by  ex- 
ternal characters,  but  by  the  results  of  actual  work,  so  nature  selects,  not  by 
special  characters  or  faculties,  but  by  that  combination  of  characters  which 
gives  the  greatest  chance  of  survival  in  the  complex,  fluctuating  environment 
in  which  each  creatures  lives.     The  species  thus  lK»comes  adapted,  first  to 


278  THE  WORLD  OF  LIFE 

Objectors  always  forget  that  a  dominant  species  has  become 
so  because  it  is  sufficiently  adapted  to  its  whole  environment, 
not  only  at  any  one  time  or  to  any  average  of  conditions, 
but  to  the  most  extreme  adverse  conditions  Avhicli  have  oc- 
curred during  the  thousands  or  millions  of  years  of  its  exist- 
ence as  a  species.  This  implies  that,  for  all  ordinary  con- 
ditions and  all  such  adverse  changes  as  occur  but  once  in  a 
century  of  a  millennium,  the  species  has  a  surplus  of  adapt- 
ability which  allows  it  to  keep  up  its  immense  population  in 
the  midst  of  countless  competitors  and  enemies.  Examples 
of  such  thoroughly  well-adapted  species  were  the  American 
bison  and  passenger  pigeon,  whose  populations  a  century  ago 
were  to  be  counted  by  millions  and  thousands  of  inillions, 
which  they  w^ere  fully  able  to  maintain  against  all  enemies 
and  competitors  then  in  existence.  But  civilised  man  has  so 
modified  and  devastated  the  whole  organic  environment  in  a 
single  century  as  to  bring  about  an  extermination  which  the 
slow  changes  of  nature  would  almost  certainly  not  have  ef- 
fected in  a  thousand  or  even  a  million  of  centuries.  This 
happened  because  the  changes  were  different  in  kind,  as  well 
as  in  rapidity, 'from  any  of  nature's  changes  during  the  whole 
period  of  the  development  of  existing  species. 

But  although  I  feel  confident  that  the  known  amount  of 
variation  would  amply  suffice  for  the  adaptation  of  any  domi- 
nant species  to  a  nomially  changing  environment,  I  admit  that 
there  are  conceivable  cases  in  which  changes  may  have  been 
so  great  and  so  comparatively  rapid  as  to  endanger  the  exist- 
ence even  of  some  of  those  species  which  had  attained  to  a 
dominant  position;  such,  for  instance,  as  the  opening  of  a  land 
passage  for  very  powerful  new  Carnivora  into  another  con- 
resist  one  danger,  then  another;  first  to  one  aspect  of  the  ever-changing 
environment,  then  to  another;  till  during  successive  generations  it  becomes 
so  perfectly  adapted  to  a  long  series  of  more  or  less  injurious  conditions, 
that,  under  all  ordinary  conditions,  it  possesses  a  surplus  of  adaptation. 
And  as  this  complete  adaptation  is  as  often  exhibited  in  colour  and  marking 
as  in  structure,  it  is  proved  that  the  transmission  of  the  effects  of  use  and 
disuse  are  not  essential  to  the  most  complex  adaptations. 


EXTEXSIO.\S  OF  DAKWJMSM  l>70 

tinent  or  extensive  area  (as  appears  to  have  occurred  with 
Africa  in  Tertiary  times),  in  ^vllicll  case  it  is  quite  possible 
that  such  an  animal  as  the  American  bison  mii^ht  have  been 
first  reduced  in  numbers,  and,  for  want  of  any  suflicieutly 
rapid  development  of  new  means  of  protection,  be  ultimately 
destroyed. 

But  a  few  years  ago  an  idea  occurred  independently  to  three 
biologists,  of  a  self-acting  jorinciple  in  nature  which  would  be 
of  such  assistance  to  any  species  in  danger  of  extermination 
as,  in  some  cases  at  all  events,  would  enable  it  to  become 
adapted  to  the  new  conditions.  It  would,  in  fact,  increase  the 
powers  of  natural  selection,  as  above  explainc(l,  to  a  degree 
which  might  sometimes  make  all  the  difference  between  life 
and  death  to  a  certain  number  of  species.  It  depends  upon 
the  w^ell-known  fact  that  the  use  of  any  limb  or  organ  strength- 
ens or  increases  the  growth  of  that  part  or  organ.  On  this 
fact  depends  all  training  for  athletics  or  games;  and  it  is 
alleged  by  some  trainers  that  any  one,  however  weak  naturally, 
can  have  his  strength  very  greatly  increased  by  systematic 
but  carefully  graded  exercise.  If,  therefore,  the  survival  of 
any  animal  in  presence  of  a  new  enemy  or  unaccustomed 
danger  depends  upon  increased  powers  of  running,  or  jumping, 
or  tree-climbing,  or  swimming,  then,  during  the  process  of 
eliminating  those  individuals  who  were  the  worst  in  these  re- 
spects, all  the  remainder  would  have  to  exercise  their  powers 
to  the  utmost,  and  would,  in  the  act  of  doing  so,  increase 
their  power  of  escaping  the  danger.  Thus  a  con-idrrable 
number  would  become  capable  of  surviving,  year  after  year,  to 
a  normal  old  age,  and  during  this  whole  period  would,  year 
by  year,  have  fresh  descendants,  and  of  these  only  the  very 
best,  the  most  gifted  naturally,  would  survive.  The  in- 
creased adaptation  during  the  life  of  the  individual  would  not 
be  transmitted,  but  the  quality  of  being  inijirovablc  during  life 
would  be  transmitted,  and  thus  additional  tim*^  and  a  consider- 
ablv  increased  ]K>])ulation  would  give  more  uuUcrials  for 
natural    selection    to    act    upon.      With    this    help    the    species 


280  THE  WOKLD  OF  LIFE 

might  become  so  rapidly  improved  that  the  danger  from  the 
new  environment  would  be  overcome,  and  a  new  type  might 
be  produced  which  would  continue  to  be  a  dominant  one  un- 
der the  new  conditions.^ 

N^ow,  while  it  must  be  admitted,  that  under  certain  con- 
ditions, and  with  certain  classes  of  adaptations,  the  normal 
effects  of  natural  selection  would  be  facilitated  by  the  aid  of 
individual  adaptation  through  use  of  organs,  yet  its  effect  is 
greatly  limited  by  the  fact  that  it  will  not  apply  to  several 
classes  of  adaptations  which  are  quite  unaffected  by  use  or 
exercise.  Such  are  the  colours  of  innumerable  species,  which 
are  in  the  highest  degree  adaptive,  either  as  protecting  them 
from  enemies,  as  a  warning  of  hidden  danger  (stings,  etc.), 
as  recognition-marks  for  young  or  for  wanderers,  or  by  mimi- 
cry of  protected  groups.  Here  the  tise  is  simply  being  seen 
or  not  seen,  neither  of  which  can  affect  the  colour  of  the 
object.  Again,  nothing  is  more  vitally  important  to  many 
animals  than  the  form,  size,  and  structure  of  the  teeth,  which 

1  As  many  readers  are  ignorant  of  the  extreme  adaptability  of  many  parts 
of  the  body,  not  only  during  an  individual  life,  but  in  a  much  shorter  period, 
I  will  here  give  an  illustrative  fact.  A  friend  of  mine  was  the  resident 
physician  of  a  large  county  lunatic  asylum.  During  his  rounds  one  morning, 
attended  by  one  of  his  assistants  and  a  warder,  he  stopped  to  converse  with 
a  male  patient  who  was  only  insane  on  one  point  and  whose  conversation 
was  very  interesting.  Suddenly  the  man  sprang  up  and  struck  a  violent 
blow  at  the  doctor's  neck  with  a  large  sharpened  nail,  and  almost  com- 
pletely severed  the  carotid  artery.  The  warder  seized  the  man,  the  assistant 
gave  the  alarm,  while  my  friend  sat  down  and  pressed  his  finger  on  the 
proper  spot  to  stop  the  violent  flow  of  blood,  which  would  otherwise  have 
quickly  produced  coma  and  death.  Other  doctors  soon  applied  proper  pres- 
sure, and  a  competent  surgeon  was  sent  for,  who,  however,  did  not  arrive 
for  more  than  an  hour.  The  artery  was  then  tied  up  and  the  patient  got 
to  bed.  He  told  me  of  this  himself  about  two  years  afterwards,  and,  on 
my  inquiry  how  the  functions  of  the  great  artery  had  been  renewed,  he 
assured  me  that  nothing  but  its  permanent  stoppage  was  possible,  that 
numerous  small  anastomosing  branches  enlarged  under  the  pressure  and 
after  a  few  months  carried  the  whole  current  of  blood  that  had  before  been 
carried  by  the  great  artery,  without  any  pain,  and  that  at  the  time  of  speak- 
ing he  was  quite  as  well  as  before  the  accident.  Such  a  fact  as  this  really 
answers  almost  the  whole  of  Herbert  Spencer's  argument  which  I  have 
quoted  at  p.  270. 


EXTEXSIONS  OF  DARWl.XLSM  i'8l 

are  wonderfully  varied  throughout  the  whole  of  th(^  VLricbrate 
sub-kingdom.  Yet  the  more  or  less  use  of  the  teeth  cannot 
be  shown  to  have  any  tendency  to  change  their  fnnii  or 
structure  in  the  special  ways  in  which  they  have  been  again 
and  again  changed,  though  it  might  possibly  have  induced 
growth  and  increased  size.  Yet  again,  the  scales  or  plates  of 
reptiles,  the  feathers  of  birds,  and  the  hairy  covering  of  mam- 
mal?, have  never  been  shown  to  have  their  special  textures, 
shape?,  or  density  modified  by  the  mere  act  of  use.  One 
common  error  is  that  cold  produces  length  and  density  of 
hair,  heat  the  reverse ;  but  the  purely  tropical  monkey-tribe 
are,  as  a  rule,  quite  as  well  clothed  with  dense  fur  as  most 
of  the  temperate  or  arctic  mammals,  while  no  birds  are  more 
luxuriantly  feather-clad  than  those  of  the  tropics.  XeitlnT 
is  it  certain  that  increased  gazing  improves  the  eyes,  or  loud 
noises  the  ears,  or  increased  eating  the  stomach ;  so  that  we 
must  conclude  that  this  aid  to  the  powers  of  natural  selection 
is  very  partial  in  its  action,  and  that  it  has  no  claim  to  the 
important  position  sometimes  given  it. 

(3)    Germinal  Seleclion,  an  Important  Eximfiion   of  the 

Theory  of  Natural  Selection 

Although  I  was  at  first  inclined  to  accept  Darwin's  view  of 
the  influence  of  female  choice  in  determining  the  development 
of  ornamental  colour  or  appendages  in  the  males,  yet,  when 
he  had  a(hhiced  his  wonderful  array  of  facts  bearing  upon 
the  question  in  the  Descent  of  Man,  the  evidence  for  any  such 
effective  choice  appeared  so  very  scanty,  and  the  ellects  im- 
puted to  it  so  amazingly  improbable,  that  T  felt  certain  that 
some  other  cause  was  at  work.  Tn  my  Tropical  Nature 
(1878)  and  in  my  Darwinism  (1889)  I  treated  the  subject 
at  considerable  length,  adducing  many  facts  to  prove  that,  even 
in  birds,  the  colours  and  ornamental  })lunies  of  the  males  were 
not  in  themselves  attractive,  but  served  merely  as  signs  of 
sexual  maturity  and  vigour.  Tn  the  case  of  insects,  especially 
in   butterflies,   where   the   phenomena   of  colour,   and   to  some 


282  THE  WOKLD  OE  LIEE 

extent  of  ornament,  are  strikingly  similar  to  those  of  birds, 
the  conception  of  a  deliberate  aesthetic  choice,  by  the  females, 
of  the  details  of  colour  marking,  and  shape  of  wings,  seemed 
almost  unthinkable,  and  was  supported  by  even  less  evidence 
than  in  the  case  of  birds. 

After  long  consideration  of  the  question  in  all  its  bearings, 
and  taking  account  of  the  various  suggestions  that  had  been 
made  by  competent  observers,  I  arrived  at  certain  conclu- 
sions which  I  stated  as  follows : 

"  The  various  causes  of  colour  in  the  animal  world  are,  molecular 
and  chemical  change  of  the  substance  of  their  integuments,  or  the 
action  upon  it  of  heat,  light,  or  moisture.  Colour  is  also  produced 
by  the  interference  of  light  in  superposed  transparent  lamellae  or  by 
excessively  fine  surface  striae.  These  elementary  conditions  for  the 
production  of  colour  are  found  everywhere  in  the  surface-structures 
of  animals,  so  that  its  presence  must  be  looked  upon  as  normal,  its 
absence  exceptional. 

"  Colours  are  fixed  or  modified  in  animals  by  natural  selection 
for  various  purposes :  obscure  or  imitative  colours  for  concealment ; 
gaudy  colours  as  a  warning;  and  special  markings  either  for  easy 
recognition  by  strayed  individuals  or  by  young,  or  to  divert  attack 
from  a  vital  part,  as  in  the  large  brilliantly  marked  wings  of  some 
butterflies  and  moths. 

"  Colours  are  produced  or  intensified  by  processes  of  develop- 
ment, either  where  the  integument  or  its  appendages  undergo  great 
extension  or  change  of  form,  or  where  there  is  a  surplus  of  vital 
energy,  as  in  male  animals  generally,  more  especially  at  the  breed- 
ing season."  ^ 

ISTow  the  idea  here  suggested,  of  all  these  strange  and  beau- 
tiful developments  of  plumage,  of  ornaments,  or  of  colour 
being  primarily  due  to  surplus  vitality  and  growth-power  in 
dominant  species,  and  especially  in  the  males,  seems  a  fairly 
adequate  solution  of  the  problem.  For  the  individuals  which 
possessed  it  in  the  highest  degree  would  survive  longest,  would 

1  Natural  Selection  and  Tropical  Nature  (new  ed.,  1895),  pp.  391-392. 
For  full  details  see  Darwinism,  chap.  x.  (1901). 


EXTENSIONS  OF  DARWINISM  283 

have  most  offspring  who  were  equally  or  even  more  hijrhly 
gifted;  and  thus  there  would  arise  a  continually  increasing 
vitality  whicli  would  be  partly  expended  in  the  further  develop- 
ment of  those  ornaments  and  plumes  which  are  its  result  and 
outward  manifestation.  The  varvine^  conditions  of  existence 
would  determine  the  particular  part  of  tlie  body  at  which  such 
accessory  ornaments  miglit  arise,  usually^  no  doubt,  directed 
by  utility  to  the  species.  Thus  the  glorious  train  of  the  pea- 
cock might  have  begim  in  mere  density  of  plumage  covering 
a  vital  part  and  one  specially  subject  to  attack  by  birrls  or 
beasts  of  prey,  and,  once  started,  these  plumes  would  continue 
to  increase  in  number  and  size,  as  being  an  outlet  for  vital 
energy,  till  at  last  they  became  so  enormously  lengthened  as 
to  become  dangerous  by  their  weight  being  a  check  to  speed 
in  running  or  agility  in  taking  flight.  This  is  already  the 
case  with  the  peacock,  which  has  some  difficulty  in  rising  from 
the  ground  and  flies  very  heavily.  Its  enemies  in  India  are 
tigers  and  all  the  larger  members  of  the  cat-tribe,  and  when 
any  of  these  approach  its  feeding-grounds  it  takes  alarm  and 
at  once  flies  up  to  the  low^er  branches  of  large  trees.  In  the 
ArgTis-pheasant  it  is  the  secondary  wing-featliers  that  are  ex- 
ceedingly long  and  broad,  so  as  to  be  almost  as  much  a  liin- 
drance  to  strong  or  rapid  flight  as  is  the  train  of  the  pea- 
cock; and  in  both  birds  these  ornamental  plumes  have  evi- 
dently reached  the  utmost  dimensions  compatible  with  the 
safety  of  the  species. 

There  can  also  be  little  doubt  that  in  manv  of  the  birds- 
of-paradise  and  of  the  humming-birds,  in  the  enormous  crest 
of  the  umbrella-bird,  in  the  huge  beaks  of  the  hornbiils  and 
the  toucans,  in  the  lenc^thv  neck  and  lec:s  of  the  flaminc:os  and 
the  herons,  these  various  oraamental  or  usefid  appen(iag(\><  liave 
reached  or  even  overpassed  the  maximum  of  utility.  In  an- 
other class  of  animals  we  have  the  same  phenomenon.  The 
expansion  of  the  wings  in  butlerflies  and  motlis  reaches  a 
maximum  in  several  distinct  families  —  the  Papilionidre,  the 
Morphidffi,  the  Bond\vces,  au'l  the   Xoctuje,  in  all  <>f  whirli  it 


2S4  THE  WORLD  OF  LIFE 

is  sometimes  from  nine  to  ten  inches.  Here,  again,  we  seem 
to  find  a  tendency  to  development  in  size,  which  has  gone  on 
from  age  to  age,  till  limits  have  been  reached  to  exceed  which 
threatens  the  existence  of  the  species. 

The  progressive  development  of  many  groups  of  animals 
affords  curious  illustrations  of  this  continuous  increase  in  bulk, 
or  in  the  size  of  particular  organs,  till  they  have  actually  over- 
passed the  line  of  permanent  safety,  and  under  the  first  ad- 
verse conditions  have  led  to  extinction.  Both  reptiles  and 
mammals  originated  in  creatures  of  small  size  which  gradually 
increased  in  bulk,  in  certain  types,  till  they  suddenly  became 
exterminated.  In  the  former  class  the  increase  was  ap- 
parently rapid,  till  the  hugest  land-animals  that  ever  lived 
appeared  upon  the  earth  —  the  Dinosauria  of  the  Jurassic  and 
Cretaceous  periods,  already  described.  Many  of  them  also  de- 
veloped strange  horns  and  teeth;  and  these,  too,  when  they 
reached  their  maximum,  also  suddenly  disappeared.  Flying 
reptiles  —  the  Pterodactyles  —  also  began  as  small  animals 
and  continually  increased,  till  those  of  the  period  of  our  Chalk 
attained  the  greatest  dimensions  ever  reached  by  a  flying  crea- 
ture, and  then  the  whole  group  became  extinct  at  a  time  when 
a  higher  type,  the  birds,  w^ere  rapidly  developing. 

With  mammals  the  case  is  even  more  striking,  all  the  ear- 
liest forms  of  the  Secondary  age  being  quite  small;  while  in 
the  Tertiary  period  they  began  to  increase  in  size  and  to  de- 
velop into  a  great  variety  of  types  of  structure ;  till,  in  an 
age  just  previous  to  our  own,  such  exceedingly  diverse  groups 
as  the  marsupials,  the  sloths,  the  elephants,  the  camels,  and 
the  deer,  all  reached  their  maximum  of  size  and  variety  of 
strange  forms,  the  most  developed  of  which  then  became  ex- 
tinct. Others  of  a  lower  and  more  generalised  type,  but 
equally  bulky,  had  successively  disappeared  at  the  termina- 
tion of  each  subdivision  of  the  Tertiary  age.  It  is  here  that 
we  can  trace  the  specialisation  and  increase  in  size  of  the 
horse-tribe  and  of  the  deer;  tlie  latter  passing  from  a  horn- 
less state  to  one  of  simple  horns,  gradually  increasing  in  size 


Fig.  94. —  MacJurrodus   neogwus    ( Sabre-Toothed   Ti<,n'r). 
From  the  Pleistocene   of  Buenos  Ayres.      One-eighth   nat.    size.      (Nicholson's 

Palaeontology.) 


Fig.  95. —  Skeleton    of    liiuiit    Deer     {Ccrrus    <ii;i(iiilruft) .      (li.M.    (Juide.) 

From   a  peat-bog  in  Ireland.      One-thirtieth   nat.   size. 

The  antlers  were  often  9  feet  across  from  tip  to  tip,  sometimes  11  feet. 


EXTENSIONS  OF  DARWINISM  285 

and  complexity  of  branching,  till  they  culminated  in  tlic  great 
Irish  elk,  which  was  the  contemporary  of  the  mammoth  and 
man  in  our  own  country. 

Dr.  A.  S.  Woodward,  keeper  of  Geology  in  the  British 
Museum,  discussed  this  curious  phcnumenou  in  his  presi- 
dential address  to  the  Geological  Section  of  the  British  Asso- 
ciation in  1909 ;  and  a  few  extracts  will  show  how  widespread 
are  these  facts,  and  the  great  interest  they  have  excited. 
After  sketching  out  the  whole  course  of  animal  development, 
and  showing  how  universal  is  the  law  (much  empliasised  by 
Darwin),  that  the  higher  form  of  one  group  never  developed 
from  similar  forms  of  a  preceding  lower  type,  but  that  both 
arose  from  an  early,  more  generalised  type,  he  says: 

*'  To  have  proved,  for  example,  that  flying  reptiles  did  not  pass 
into  birds  or  bats,  that  hoofed  Dinosaurs  did  not  change  into 
hoofed  mammals,  and  that  Ichthyosaurs  did  not  become  porpoises, 
and  to  have  shown  that  all  these  later  animals  were  mere  mimics 
of  their  ^predecessors,  originating  independently  from  a  higher  yet 
generalised  stock,  is  a  remarkable  achievement." 

Then  comes  a  reference  to  the  subject  we  are  now  discuss- 
ing: 

"  Still  more  significant,  howeve-r,  is  the  discovery,  that  towards 
the  end  of  their  career  through  geological  time,  totally  difTerent 
races  of  animals  repeatedly  exhibit  certain  peculiar  features  which 
can  only  be  described  as  infallible  marks  of  old  age.  The  growth 
to  a  very  large  size  is  one  of  these  marks,  as  we  observe  in  the 
giant  Pterodactyls  of  the  Cretaceous  i^eriod,  the  colossal  Dinosaurs 
of  the  Upper  Jurassic  and  Cretaceous,  and  the  large  mammals  of 
the  Pleistocene  and  the  present  day.  It  is  not,  of  course,  all  the 
members  of  a  race  that  increase  in  size;  some  remain  small  until 
the  end,  and  they  generally  survive  long  after  the  others  are  ex- 
tinct. 

"Another  frequent  mark  of  old  age  In  races  was  first  discussed 
and  clearly  pointed  out  by  Professor  C.  E.  Beechor  of  Yale.  It  is 
the  tendency  of  all  animals  with  skeletons  to  produce  a  superfluity 
of  dead  matter,  which  accumulates  in  the  form  of  spines  or  bosses 


28G  THE  WOKLD  OF  LIFE 

as  soon  as  the  race  they  represent  has  reached  its  prime  and  begins 
to  be  on  the  down  grade.  Among  famiUar  instances  may  be  men- 
tioned the  curiously  spiny  Graptolites  at  the  end  of  the  Silurian,  the 
horned  Pariasaurians  at  the  beginning  of  the  Trias,  the  armour- 
plated  and  horned  Dinosaurs  at  the  end  of  the  Cretaceous,  and  the 
cattle  or  deer  of  modern  Tertiary  times.  .  .  .  The  growth  of 
these  excrescences,  both  in  relative  size  and  complication,  was  con- 
tinual and  persistent  until  the  climax  was  reached  and  the  extreme 
forms  died  out.     ... 

"  It  appears,  indeed,  that  when  some  part  of  an  animal  (whether 
an  excrescence  or  a  normal  structure)  began  to  grow  relatively 
large  in  successive  generations  during  geological  time,  it  often  ac- 
quired some  mysterious  impetus  by  which  it  continued  to  increase 
long  after  it  had  reached  the  serviceable  limit.  The  unwieldy 
antlers  of  the  extinct  Sedgwick's  deer  and  Irish  deer  (Fig.  95), 
for  example,  must  have  been  impediments  rather  than  useful 
weapons.  Tlie  excessive  enlargement  of  the  upper  canine  teeth  in 
the  sabre-toothed  tigers  (Machaerodus  and  its  allies)  must  also 
eventually  have  hindered  rather  than  aided  the  capture  and  eating 
of  prey.''  ^ 

Dr.  Woodward  further  remarks: 

"  The  curious  gradual  elongation  of  the  face  in  the  Oligocene 
and  Miocene  Mastodons  can  only  be  regarded  as  another  illustra- 
tion of  the  same  phenomenon.  In  successive  generations  of  these 
animals  the  limbs  seem  to  have  grown  continually  longer,  while  the 
neck  remained  short,  so  that  the  head  necessarily  became  more  and 
more  elongated  to  crop  the  vegetation  on  the  ground.  A  limit  of 
mechanical  efficiency  was  eventually  reached,  and  then  there  sur- 
vived only  those  members  of  the  group  in  which  the  attenuated 
mandibles  became  shortened,  leaving  the  modified  face  to  act  as  a 

1  The  species  Maclicerodus  neogceus,  the  skull  of  which  is  shewn  in  Fig.  94, 
appears  lo  have  had  the  largest  canines  of  any  species  of  the  genus;  and  we 
are  told  by  Messrs.  Xicholson  and  Lydekker  (Manual  of  Palaeontology^  ii.  p. 
1449)  that  the  upper  carnassial  tooth  (the  fourth  premolar)  "has  four 
distinct  lobes,  and  is  thus  the  most  complex  example  of  this  type  of  tooth 
known."  The  canines  were  about  9  inches  long  (more  than  half  the  length 
of  the  whole  skull),  and  very  massive  in  proportion.  It  became  extinct  in 
South  America  in  the  Pleistocene  period,  about  the  same  time  as  the  last  of 
the  European  species. 


exte^sio:n's  of  darwixism 


28' 


proboscis.  Tlie  elephants  thus  arose  as  a  kind  of  aftertlioiiglit 
from  a  group  of  quadrupeds  that  were  rapidly  approaching  tlicir 
doom."     (See  figures  in  last  chapter,  p.  :^-")7.) 

This  last  is  a  specially  interesting  case,  because  it  is  the 
only^  one  in  which,  without  change  of  general  environnifnt, 
or  apparently  of  habits,  a  highly  developed  animal  has  re- 
traced its  latest  steps,  and  then  advanced  in  a  new  line  of  de- 
velopment, leading  to  the  wonderful  trunk  and  the  cnurmous 
tusks  of  the  modern  elephant,  as  explained  in  Chapter  XIT. 
That  these  have  now  attained  the  maximum  of  useful  growth 
is  indicated  bv  the  fact  that  amoni>:  the  extinct  fonus  are  those 
in  which  they  are  developed  to  an  unwieldy  size,  as  in  Elephas 
ganesa  of  Xorth-West  India,  whose  slightly  curved  tusks,  some- 
times nearly  10  feet  long,  must  have  put  an  enormous  strain 
upon  the  neck,  and  the  mammoth,  whose  greatly  curved  tusks 
were  almost  equally  heavy. 

Excessive  Development  of  Lower  Animals  before  Extinction 

My  friend  Professor  Judd  has  called  my  attention  to  the 
fact  that  many  of  the  lower  forms  of  life  exhibited  similar 
phenomena.  The  Trilobites  (primitive  crustaceans)  which 
were  extremely  abundant  in  the  Pala?ozoic  rocks,  in  their  last 


Fig.  96. —  Conocoryphc  sultzcri. 
Upper   Cambrian. 


Fio.  97. —  Paradonides  bohcmicus. 
Upper  Cambrian. 


288 


THE  WORLD  OF  LIFE 


stages  "  developed  strange  knobs  and  spikes  on  their  shells,  so 
that  thej  seemed  to  be  trying  experiments  in  excessive  vari- 
ation.'^ 

Figs.  96,  97^  show  typical  forms  of  Trilobites  (so  called 
from  their  three-lobed  bodies)  ;  while  at  a  later  period,  when 
the  whole  group  was  approaching  extinction,  it  produced 
spined  forms  like  that  shown  in  Fig.  98. 

Excentric  forms  of  Ammonites 

At  a  later  period  the  wonderfully  rich  and  varied  Am- 
monites show  still  more   curious  changes.     Beginning  in  the 

Devonian  formation  thev  increased 
in  varietv  of  form  and  structure 
all  through  the  succeeding  forma- 
tions, till  they  finally  died  out  in 
the  Cretaceous.  The  two  species 
here  figured  from  the  Trias  (Figs. 
99,  100)  may  be  taken  as  typical; 
but  the  variations  in  surface  pat- 
tern are  almost  infinite.  Visitors 
to  Weymouth  or  Lyme  Regis  maj" 
find  such  in  abundance  under  Lias 
cliffs,  or  in  the  former  place 
along  the  shores  of  the  backwater. 
As  time  went  on  Ammonites  in- 
FiG.   ^^  —  Acidaspis  dufrenoyi.    creased  in  maximum  size,  till  in 

Silurian    (Bohemia). 

the  Chalk  formation  specimens  2 
or  3  feet  diameter  are  not  uncommon.  One  of  the  largest 
English  specimens  in  the  British  Museiim  (Xatural  History) 
was  found  at  Rottingdean,  near  Brighton,  and  is  3  feet  8  inches 
across;  but  the  largest  known  is  an  allied  species  from  the 
Upper  Chalk  of  Westphalia,  and  has  the  enormous  diameter 
of  6  feet  8  inches. 

It  is  an  interesting  fact  that  the  very  earliest  Ammonites 
were  straight,  and  gradually  became  closely  coiled.  This 
form    was    maintained    almost    constant    throu2:hout    the    vast 


EXTENSIONS  OF  DARWINISM 


289 


periods  of  the  Mesozoic  age,  till  towards  llie  end,  when  the 
whole  race  was  about  to  die  out,  they  seemed  to  try  to  go 
back  to  their  original  form,  which  some  almost  reached   (Fi^. 


Fig.    99. —  Ceratites    nodosus. 
Trias. 


Fig.    100. —  Trachyceras    aon. 
Trias. 


105),  while  others,  as  Professor  Judd  remarks  (in  a  letter), 
"  before  finally  disappearing,  twisted  and  untwisted  them- 
selves, and  as  it  were  wriggled  themselves  into  extraordinary 


Fig.    101. —  Crioceras    emerici. 
Cretaceous. 


Fig.  102. —  Ileteroceras  cmcrici. 
Cretaceous. 


shapes,  in  the  last  throes  of  dissolution.'-  These  strange  forms 
(Figs.  90-106)  are  reproduced  from  Nicholson's  PaUeontol- 
ogy,  and  there  are  many  others. 


290 


THE  WOKLD  OF  LIFE 


Fig.   103. —  Macroscapliites  ivanii. 
Cretaceous.  ' 


Fig.  104. —  Hamites  rotundus. 

Cretaceous. 


Fig.  105. —  Ptychoceras  emericianum. 

Cretaceous. 


Fig.  lOG. —  Ancyloceras  Matheronianum. 

Gault. 
Late   Ammonites.      (From   Nicholson's   Palaeontology.) 

Special  Features  in  the  Development  of  Vertehrates 

Another  remarkable  fact  dwelt  upon  in  Dr.  Woodward's 
address  is  the  remarkably  small  brains  of  those  early  types 
of  vertebrates  which  were  not  destined  to  survive.     The  most 


EXTE:^rSIOXS  of  DARWIXISM  291 

striking  cases  are  those  of  the  Mesozoic  reptiles  and  the  early 
Tertiary  ungulate  mammals,  which  both  increased  to  such  an 
enormous  bulk,  yet  retained  throughout  an  almost  ludicrously 
small  brain,  as  described  in  the  last  chapter.  The  same  was 
the  case  to  a  somewhat  less  extent  with  the  carnivorous  mam- 
mals, the  Creodonta  and  Sparassodonta  of  the  early  Tertiaries 
both  of  the  eastern  and  western  hemispheres.  These  were 
sometimes  as  large  as  lions  or  bears,  and  had  equally  well  de- 
veloped canine  teeth,  but  very  small  brains;  and  they  all  died 
out  in  Eocene  or  early  Miocene  times,  giving  way  to  small  an- 
cestral forms  of  our  modern  carnivores,  which  then  increased 
in  size  and  developed  larger  brains,  culminating  in  the  highly 
intelligent  fox  and  dog,  cat  and  leopard,  of  our  own  day. 

Yet  another  singular  feature  of  some  of  the  more  highly 
developed  vertebrates  is  the  partial  or  total  loss  of  teeth.  This 
is  well  shown  in  the  camels,  which  have  only  a  pair  uf  in- 
cisors in  the  upper  jaw;  while  the  whole  vast  family  of  the 
deer,  cattle,  and  sheep  have  a  completely  toothless  pad  in  the 
front  of  the  upper  jaws.  This  is  apparently  better  adapted 
for  rapid  browsing  of  grass  and  low  herbage  —  whieli  is  stored 
up  in  the  23aunch  for  rumination  when  at  rest;  and  the  ab- 
sence of  teeth  as  a  defence  is  compensated  by  the  possession 
of  horns  in  a  great  variety  of  form  and  structure. 

Even  more  remarkable  is  the  total  loss  of  teeth  bv  modern 
birds,  although  the  early  types  of  birds  possessed  them.  The 
bill,  however,  is  often  a  very  effective  piercing  or  tearing 
weapon ;  and  their  strongly  grasping  claws  and  hooked  bill 
render  the  birds  of  prey  almost  as  powerful  and  d instructive 
as  the  smaller  members  of  the  cat-tribe.  This  partial  or  total 
disappearance  of  the  teeth  has  no  doubt  been  helped  on  l)y  the 
same  principle  which  led  to  the  persistent  increase  of  useless 
appendages  till  checked  by  natural  selection  or  till  it  led  to 
the  extinction  of  the  entire  race. 


292  THE  WORLD  OF  LIFE 

Germinal  Selection 

The  numerous  and  varied  phenomena  which  have  been 
merely  sketched  in  outline  in  the  present  chapter  receive  an 
approximate  explanation  by  Professor  Weismann's  theory  of 
germinal  selection,  which  he  first  published  in  1896.  He 
appears  to  have  been  led  to  it  by  feeling  the  difficulty  of  ex- 
plaining many  of  these  phenomena  by  the  ^'  natural  selection  " 
of  Darwin;  but  to  have  laid  more  stress  on  those  of  Section  2 
of  the  present  chapter  than  those  of  Section  3.  He  had  in 
1892  published  his  elaborate  volume  on  The  Germ-Plasm  a 
Theory  of  Heredity,  to  which  this  later  theory  is  a  logical 
sequel. 

During  the  last  quarter  of  a  century  many  striking  discov- 
eries have  been  made  in  what  may  be  termed  the  mechanism 
of  growth  and  reproduction ;  each  successive  advance  in  micro- 
scopic power  and  methods  of  observation  have  brought  to  light 
whole  worlds  of  complex  structure  and  purposive  transfor- 
mations in  w^hat  was  before  looked  upon  as  structureless  cells 
or  corpuscles.  Some  attempt  will  be  made  in  a  later  chapter 
to  discuss  these  primary  life-phenomena;  here  it  is  only  neces- 
sary to  show  briefly  how  Weismann's  new  theory  helps  us  to 
understand  the  facts  of  life-development  we  have  been  dealing 
with.  For  this  purpose  I  cannot  do  better  than  quote  Pro- 
fessor Lloyd  Morgan's  very  clear  statement  of  the  theory. 
He  says :  ^ 

"  The  additional  factor  which  Dr.  Weismann  suggests  is  what 
he  terms  ^  germinal  selection.'  This,  briefly  stated,  is  as  follows :  — 
There  is  a  competition  for  nutriment  among  those  parts  of  the  germ 
named  determinants,  from  which  the  several  organs  or  groups  of 
organs  are  developed.  In  this  competition  the  stronger  deter- 
minants get  the  best  of  it,  and  are  further  developed  at  the  expense 
of  the  weaker  determinants,  which  are  starved,  and  tend  to  dwin- 
dle and  eventually  disappear.  The  suggestion  is  interestingj  but 
one  well-nigh  impossible  to  test  by  observation.     If  accepted  as  a 

1  Habit  and  Instinct,  p.  310. 


EXTEJN^SIO^^S  OF  DAKWINISM  293 

factor,  it  would  seiTe  to  account  for  the  inordinate  growth  of  cer- 
tain structures,  such  as  the  exuberance  of  some  secondary  sexual 
characters,  and  for  the  existence  of  determinate  variations,  that  is 
to  say,  variations  along  special  or  particular  lines  of  adaptation." 

It  may  be  well  to  give  here  Weismann's  own  definition  of 
what  he  means  by  "  determinants,"  as  quoted  by  Professor  J. 
Arthur  Thomson  in  his  fine  volume  on  Heredity  (p.  435) : 

" '  I  assume,'  Weismann  says,  ^  that  the  germ-plasm  consists  of 
a  large  number  of  different  parts,  each  of  which  stands  in  a  definite 
relation  to  particular  cells  or  kinds  of  cells  in  the  organism  to  be 
developed  —  that  is,  tliey  are  *  primary  constituents'  in  the  sense 
that  their  co-operation  in  the  production  of  a  particular  part  of  the 
organism  is  indispensable,  the  part  being  determined  both  as  to  its 
existence  and  its  nature  by  the  predestined  particles  of  the  germ- 
plasm.  I  therefore  call  these  Determinants,  and  the  parts  of  the 
complete  organism  which  they  determine  Determinates,"  ^ 

Professor  Thomson  continues  thus: 

"  But  how  many  determinants  are  to  be  postulated  in  any  given 
case?  "Weismann  supposes  that  every  independently  variable  and 
independently  heritable  character  is  represented  in  the  germ-plasm 
by  a  determinant.  A  lock  of  white  hair  among  the  dark  may  re- 
appear at  the  same  place  for  several  generations;  it  is  difficult  to 
interpret  such  facts  of  particular  inheritance  except  on  the  theory 
that  the  germ -plasm  is  built  up  of  a  large  number  of  different  de- 
terminants. It  may  be  pointed  out  that  almost  all  biologists  who 
have  tried  to  form  a  conception  of  the  ultimate  structure  of  living 
matter  have  been  led  to  the  assumption  —  expressed  in  very  varied 
phraseology  —  of  ultimate  protoplasmic  units  which  have  the  power 
of  growth  and  division.  It  is  in  no  way  peculiar  to  Weismann  to 
imagine  biophors  and  to  credit  them  with  the  powers  of  growing 
and  dividing.'' 

I  quote  these  passages  because  Professor  Thomson  is  thor- 
oughly acquainted,  not  only  with  all  Weismann's  work,  having 
himself  translated  some  of  them,  but  also  with  that  of  other 

1  The  Evolution  Theory,  1004.  vol.   i.  p.  355. 


294  THE  WOELD  OF  LIFE 

European  and  American  writers  on  this  very  difficult  prob- 
lem; and  he  arrives  at  the  conclusion,  that  Weismann's  theory 
is  the  most  carefully  and  logically  worked  out,  and  that  some 
such  conception  is  essential  for  a  comprehension  of  the  won- 
derfully complex  phenomena  of  heredity.  He  also  quite 
agrees  with  the  conception  that  as  these  vital  elements  of  the 
germ-plasm  grow  and  multiply  during  the  life  of  the  organism, 
they  must  be  nourished  by  fluids  derived  from  it,  and  that 
there  must  be  slight  differences  between  them  in  size  and 
vigour,  and  a  struggle  for  existence  in  which  the  most  vigorous 
survive.  These  more  vigorous  determinants  will  lead  to  more 
vigorous  growth  of  the  special  part  or  organ  they  determine  — 
hair,  horns,  ornaments,  etc., —  and  wherever  this  increase  is 
useful,  or  even  not  hurtful,  to  the  species,  it  will  go  on  in- 
creasing, generation  after  generation,  by  the  survival  of  more 
and  more  vigorous  determinants. 

There  is  therefore  both  an  internal  and  an  external  strug- 
gle for  existence  affecting  all  the  special  parts  —  organs,  or- 
naments, etc. —  of  ever}^  living  thing.  With  regard  to  the 
more  important  sti-uctures,  such  as  the  limbs,  the  organs  of 
vision  and  hearing,  the  teeth,  stomach,  heart,  lungs,  etc.,  on 
Avhich  the  very  existence  of  the  individual  as  well  as  of  the 
species  depends,  survival  of  the  fittest  in  due  co-ordination 
with  all  other  parts  of  the  body  will  continually  check  any 
tendency  to  unbalanced  development,  and  thus,  generation  by 
generation,  suppress  the  tendency  of  the  more  vigorous  de- 
terminants to  increase  the  growth  and  vigour  of  its  special 
determinates,  by  elimination  of  the  individuals  which  exhibit 
such  unbalanced  gro^vth.  But  in  the  case  of  appendages,  or- 
naments, or  brilliant  colours,  which  may  begin  as  a  mere  out- 
let for  superfluous  vital  energy  in  dominant  races,  and  then 
be  selected  and  utilised  for  purposes  of  recognition,  warning, 
imitative  concealment,  or  for  combat  among  males,  there  w^ill 
not  be  the  same  danger  to  the  ver)^  existence  of  the  adult  ani- 
mal. It  will,  however,  often  happen  that  the  increase  through 
germinal  selection  Avill  continue  beyond  the  point  of  absolute 


EXTENSlOiVS  OF  DxVK\VI.\i;SM  205 

utility  to  tlie  individual;  between  which  and  the  jooint  of  ef- 
fective hurtfulness  there  may  be  a  considerable  margin.  In 
this  way  w^e  have  a  quite  intelligible  exi)lanation  of  the  enor- 
mous development  of  feathers  or  decorative  pi  Limes  in  so  many 
birds,  enormous  horns  in  deer  and  antelopes,  huge  tusks  in 
elephants,  and  huge  canine  teeth  in  other  quadrupeds.  Tliis 
view  is  supported  by  the  suggestive  fact,  that  many  of  these 
appendages  are  retained  only  for  a  short  period,  during  the 
breeding  season,  when  vigour  is  greatest  and  food  most  abun- 
dant, and  when  therefore  they  are  least  injurious. 

Again,  when  acting  in  an  opposite  direction,  the  theory 
serves  to  explain  the  rapid  dwindling  and  final  disappearance 
of  some  useless  organs,  which  mere  disuse  is  hardly  sufficient 
to  explain;  such  are  the  lost  hind  limbs  of  whales,  llie  rudi- 
mentary wings  of  the  Apteryx,  the  toothless  beak  of  birds,  ete. 
In  such  cases,  after  natural  selection  had  reduced  the  part  to 
a  rudimental  condition,  any  regrowth  would  be  injurious,  and 
thus  determinants  of  increased  vigour  would  be  suppressed 
by  the  non-survival  of  the  adult,  leaving  the  weaker  deter- 
minants to  be  crowded  out  by  the  competition  of  those  of  ad- 
jacent parts,  the  increased  development  of  which  was  ad- 
vantageous. 

By  this  very  ingenious,  but,  though  speculative,  highly 
probable  hypothesis,  extending  the  s]:)hero  of  c<inipetition  for 
nourishment  and  survival  of  the  fittest  from  \\\o  nTgani>=m  as 
a  whole  to  some  of  its  elementarv  vital  units,  Professor  Weis- 
mann  has,  I  think,  overcome  the  one  real  diHieulty  in  the  in- 
terpretation of  the  external  forms  of  living  things,  in  all  their 
marvellous  details,  in  tenns  of  normal  .variation  and  survival 
of  the  fittest.  We  have  here  that  '^  mysterious  impetus  "  to 
increase  beyond  the  useful  limit  which  Dr.  Woodward  has  rt^ 
ferred  to  in  his  address  already  quoted,  and  which  is  also 
a  cause  of  the  extinction  of  species  to  which  Mr.  Lydekker 
referred  us,  as  quoted  towards  the  end  of  the  preceding  chap- 
ter. 


296  THE  WORLD  OF  LIFE 

Illustrative  Cases  of  Extreme  Development 

Two  examples  of  this  extreme  development  have  not,  I 
think,  jet  been  noticed  in  this  connection.  The  wonderful 
long  and  perfectly  straight  spirally  twisted  tusk  of  the  strange 
Cetaceous  mammal,  the  narw^hal,  is  formed  by  an  extreme  de- 
velopment, in  the  male  only,  of  one  of  a  pair  of  teeth  in  the 
upper  jaw.  All  other  teeth  are  rudimentary,  as  is  the  right 
tooth  of  the  pair  of  which  the  left  forms  the  tusk,  often  7 
or  8  feet  long,  and  formed  of  a  very  fine  heavy  ivory.  The 
use  of  this  is  completely  unknown,  for  though  two  males  have 
been  seen  playing  together,  apparently,  with  their  tusks,  they 
do  not  fight,  and  their  food,  being  small  Crustacea  and  other 


Fig.  107. —  Head  of  Babirusa  {Bahirusa  alfurus). 
The  tusks  of  this  animal  continue  growing  during  life.      Those  of  the  upper  jaw  are 
directed  upward  from  the  base  so  that  they  do  not  enter  the  mouth,  but  pierc- 
ing the  skin  of  the  face,  resemble  horns  rather  than  teeth,  and  curve  backwards 
and  downwards.      (Flower,  Study  of  Mammals.) 

marine  animals,  can  have  no  relation  to  this  weapon.  We 
may,  however,  suppose  that  the  tusk  was  originally  developed 
as  a  defence  against  some  enemy,  when  the  narwhal  itself  was 
smaller,  and  had  a  wider  range  beyond  the  Arctic  seas  which 
it  now  inhabits;  and  when  the  enemv  had  become  extinct  this 
strange  weapon  went  on  increasing  through  the  law  of  germinal 
selection,  and  has  thus  become  useless  to  the  existing  animaL 


EXTEiS^SIOXS  OF  DAEWIXISM  297 

The  other  case  is  that  of  the  equally  remarkable  Babinisa 
of  the  islands  of  Celebes  and  Burn,  in  which  the  canines  of 
the  males  are  so  developed  as  to  be  useless  for  fighting-  (see 
Fig.  107).  Here,  too,  there  can  be  little  doubt  that  the  tusks 
were  originally  of  the  same  type  as  in  the  wild  boar,  and  were 
used  for  both  attack  and  defence;  but  the  ancestral  form  hav- 
ing been  long  isolated  in  a  country  where  there  were  no  ene- 
mies of  importance,  natural  selection  ceased  to  preser\'e  thom 
in  their  original  useful  form,  and  the  initial  curvature  became 
increased  by  germinal  selection,  while  natural  selection  only 
checked  such  developments  as  would  be  injurious  to  the  in- 
dividuals which  exhibited  them. 

A  Wider  Application  of  the  Principle  of  Germ-Selection 

But  it  seems  to  me  that  the  principle  here  suggested  has  a 
still  higher  importance,  inasmuch  as  it  has  been  the  normal 
means  of  adding  to  and  intensifying  that  endless  varietv  of 
form,  that  strange  luxuriance  of  outgrowths,  and  that  ex- 
quisite beauty  of  marking  and  brilliancy  of  colour,  that  ren- 
der the  world  of  life  an  inexpressible  delight  to  all  who  have 
been  led  to  observe,  to  appreciate,  or  to  study  it.  It  is  through 
the  action  of  some  such  internal  selecting  agency  that  we  owe 
much  of  what  we  must  call  the  charming  eccentricity  of  nature 
—  of  those  exuberances  of  growth  which  cause  the  nature- 
lover  to  perpetually  exclaim,  "  What  can  be  the  use  of  this  ?  '* 
In  the  birds-of-paradise  we  had  long  known  of  the  tail- 
feathers,  the  breast-shields,  the  masses  of  plumage  from  under 
the  wings,  the  crests,  the  neck-tippets,  all  in  wonderful  variety 
of  shape  and  colour.  Then,  in  the  island  of  Batch iau  1  ob- 
tained a  bird  in  which  from  the  bend  of  the  wing  (correspond- 
ing to  our  wrist)  there  spring  two  slender  and  flexible  white 
feathers  on  each  side  standine;  out  from  the  wine:  durinc:  ilii^ht, 
whence  it  has  been  termed  the  standard-winged  bird-of-para- 
dise.  Again,  a  few  years  ago,  there  was  discovered  in  the 
mountains  of  German  'New  Guinea  another  quite  new  type,  in 
which,  from  the  corner  of  each  eye,  a  long  plume  arises  more 


208  THE  WORLD  OF  LIFE 

than  twice  the  length  of  the  bird's  body,  and  having,  on  one 
side  only  of  the  midrib,  a  series  of  leaf-shaped  thin  horny 
plates  of  a  beautiful  light-blue  colour  on  the  upper  surface, 
contrasting  in  a  striking  manner  with  the  purple  black,  ochre 
yellow,  and  rusty  red  of  the  rest  of  the  plumage. 

In  the  comparatively  small  number  of  birds-of -paradise 
now  known,  we  have  a  series  of  strange  ornamental  plumes 
w^hich  in  their  shape,  their  size,  their  colours,  and  their  point 
of  origin  on  the  bird,  exhibit  more  varietv  than  is  found  in 
any  other  family  of  birds,  or  perhaps  in  all  other  known  birds ; 
and  we  can  now  better  explain  this  by  the  assistance  of  Weis- 
mann's  law  in  a  highly  dominant  group  inhabiting  a  region 
which  is  strikin^'lv  deficient  in  animals  wdiich  are  inimical  to 
bird-life  in  a  densely  forest-clad  country. 

To  this  same  principle  we  must,  I  think,  impute  that  su- 
perfluity of  dazzling  colour  in  many  birds,  but  more  especially 
in  many  insects,  in  which  it  so  often  seems  to  go  far  beyond 
usefulness  for  purposes  of  recognition,  or  as  a  warning,  or  a 
distracting  dazzle  to  an  attacking  enemy. 

Even  in  the  vegetable  kingdom  this  same  law  may  have 
acted  in  the  production  of  enoiTQOus  masses  of  flowers  or  of 
fruits,  far  beyond  the  needful  purpose  of  perpetuating  the 
species ;  and  probably  also  of  those  examples  of  excessive  bril- 
liancy of  colour,  as  in  the  intense  blues  of  many  gentians,  the 
vivid  scarlet  of  the  Cardinal  lobelia,  or  the  glistening  yellow 
of  many  of  our  buttercups.  It  is  quite  possible,  therefore, 
that  to  this  principle  of  ^'  germinal  selection  "  we  owe  some 
of  the  most  exquisite  refinements  of  beauty  amid  the  endless 
variety  of  form  and  colour  both  of  the  animal  and  the  veg- 
etable world. 

We  may  also  owe  to  it  the  superabundant  production  of  sap 
which  enabled  the  early  colonists  of  America  to  make  almost 
imlimited  quantities  of  sugar  from  the  '^  sugar  maple." 
Each  tree  will  yield  about  four  pounds  of  sugar  yearly  from 
about  thirty  gallons  of  sap ;  and  it  is  stated  by  Lindley  that  a 
tree  wull  yield  this  quantity  for  forty  years  without  being  at 


EXTENSIONS  OF  DARWINISM  299 

all  injured;  and  large  quantities  of  such  sugar  are  still  made 
for  home  consumption,  the  molasses  produced  from  ii  l)oing 
said  to  be  superior  in  flavour  to  that  from  the  sugar-cane. 
Here  surely  is  a  verv  renuirkable  case  of  an  excessive  sur- 
plus product  which  is  of  gTcat  use  to  man,  and,  so  far  as 
we  can  see,  to  man  only.  The  same  phenomenon  of  a  sur- 
plus product  is  presented  by  the  Para  rubber-trees  (Sii)h«jnia, 
many  species),  from  which,  at  the  pro]ier  season,  larttc  quan- 
tities of  the  precious  sap  can  be  withdrawn  annually  for  very 
long  periods,  without  injuring  the  trees,  or  producing  a  dimi- 
nution of  the  supply.  There  are  also  many  other  useful  veg- 
etable products,  among  those  referred  to  in  our  fifteenth  chaj)- 
ter,  to  which  the  same  remark  will  apply ;  and  it  seems  prrib- 
able  that  we  owe  the  whole  of  these,  and  many  others  not  yet 
discovered  in  the  vast  unexplored  tropical  forests,  to  this  far- 
reaching  principle  of  "  germinal  selection.'^ 

General  Conclusions  as  to  Life-Development 

Before  quitting  the  subject  of  the  course  of  development  of 
the  entire  world  of  life  as  shown  by  the  geological  record,  to 
which  the  present  chapter  is  in  a  measure  supplementary,  it 
will  be  w^ell  to  say  something  as  to  its  broader  features  from 
the  point  of  view  adopted  in  this  work.  This  is,  that  beyond 
all  the  phenomena  of  nature  and  their  immediate  causes  and 
laws  there  is  Mind  and  Purpose;  and  that  the  ultimate  pur- 
pose is  (so  far  as  we  can  discern)  the  development  of  mankind 
for  an  enduring  spiritual  existence.  With  this  object  in  view- 
it  would  be  important  to  supply  all  possible  aids  that  a  ma- 
terial world  can  give  for  the  training  and  education  of  man's 
higlier  intellectual,  moral,  and  aesthetic  nature.  If  this  view 
is  the  true  one,  we  may  look  upon  our  Universe,  in  all  its  parts 
and  durinc;  its  whole  existence,  as  slowlv  ]>ut  surelv  marchiui:: 
onwards  to  a  predestined  end ;  and  this  involves  the  further 
conception,  that  now  that  man  /m.s^  boon  dovolojiod,  tliat  lio  is 
in  full  possession  of  this  earth,  and  that  upon  his  proper  use 
of  it  his  adequate  preparation  for  the  future  life  depends,  then 


300  THE  WORLD  OF  LIFE 

a  great  responsibility  is  placed  upon  him  for  the  way  in  which 
he  deals  with  this  his  great  heritage  from  all  the  ages,  not  only 
as  regards  himself  and  his  fellows  of  the  present  generation, 
but  towards  the  unknown  multitude  of  future  generations  that 
are  to  succeed  him. 

x\ll  of  us  who  are  led  to  believe  that  there  must  be  a  being 
or  beings  high  and  powerful  enough  to  have  been  the  real 
cause  of  the  material  cosmos  with  its  products  life  and  mind, 
can  hardly  escape  from  the  old  and  much-derided  view,  that 
this  world  of  ours  is  the  best  of  all  possible  worlds  calculated 
to  bring  about  this  result.  And  if  the  best  for  its  special  pur- 
pose, then  the  whole  course  of  life-development  was  the  best; 
then  also  every  step  in  that  development  and  every  outcome 
of  it  which  we  find  in  the  living  things  which  are  our  con- 
temporaries are  also  the  best  —  are  here  for  a  purpose  in  some 
way  connected  with  us;  and  if  in  our  blind  ignorance  or 
prejudice  we  destroy  them  before  we  have  earnestly  endeav- 
oured to  learn  the  lesson  thev  are  intended  to  teach  us,  w^e 
and  our  successors  will  be  the  losers  —  morally,  intellectually, 
and  perhaps  even  physically. 

Already  in  the  progress  of  this  work  I  have  dwelt  upon  the 
marvellous  variety  of  the  useful  or  beautiful  products  of  the 
vegetable  and  animal  kingdoms  far  beyond  their  o^^TL  uses,  as 
indicating  a  development  for  the  ser^uce  of  man.  This  variety 
and  beauty,  even  the  strangeness,  the  ugliness,  and  the  unex- 
pectedness we  find  everywhere  in  nature,  are,  and  therefore 
were  intended  to  be,  an  important  factor  in  our  mental  de- 
velopment ;  for  they  excite  in  us  admiration,  wonder,  and 
curiosity  —  the  three  emotions  which  stimulate  first  our  at- 
tention, then  our  determination  to  learn  the  how  and  the  why, 
which  are  the  basis  of  observation  and  experiment  and  there- 
fore of  all  science  and  all  philosophy.  These  considerations 
should  lead  us  to  look  upon  all  the  works  of  nature,  animate  or 
inanimate,  as  invested  with  a  certain  sanctity,  to  be  used  by 
us  but  not  abused,  and  never  to  be  recklessly  destroyed  or  de- 
faced.    To  pollute  a  spring  or  a  river,  to  exterminate  a  bird 


EXTENSIONS  OF  DARWINISM  301 

or  beast,  should  be  treated  as  moral  offences  and  as  social 
crimes;  while  all  who  profess  religion  or  sincerely  believe  in 
the  Deity  —  the  designer  and  maker  of  this  world  and  of  every 
living  thing  —  should,  one  would  have  thought,  have  placed 
this  among  the  first  of  their  forbidden  sins,  since  to  deface 
or  destroy  that  which  has  been  brought  into  existence  for  the 
use  and  enjoyment,  the  education  and  elevation  of  the  human 
race,  is  a  direct  denial  of  the  wisdom  and  goodness  of  the 
Creator,  about  which  thej  so  loudly  and  persistently  prate  and 
preach. 

Yet  during  the  past  century,  which  has  seen  those  great  ad- 
vances in  the  Tcnowledge  of  Nature  of  which  we  are  so  proud, 
there  has  been  no  corresponding  development  of  a  love  or  rev- 
erence for  her  works ;  so  that  never  before  has  there  been  such 
widespread  ravage  of  the  earth's  surface  by  destruction  of 
native  vegetation  and  with  it  of  much  animal  life,  and  such 
wholesale  defacement  of  the  earth  by  mineral  workings  and 
by  pouring  into  our  streams  and  rivers  the  refuse  of  manufac- 
tories and  of  cities;  and  this  has  been  done  by  all  the  greatest 
nations  claiming  the  first  place  for  civilisation  and  religion ! 
And  what  is  Avorse,  the  greater  part  of  this  waste  and  devas- 
tation has  been  and  is  being  carried  on,  not  for  any  good  or 
worthy  purpose,  but  in  the  interest  of  personal  greed  and 
avarice;  so  that  in  every  case,  while  wealth  has  increased  in 
the  hands  of  the  few,  millions  are  still  living  without  the  bare 
necessaries  for  a  healthy  or  a  decent  life,  thousands  dying 
yearly  of  actual  starvation,  and  other  thousands  being  slowly 
or  suddenly  destroyed  by  hideous  diseases  or  accidents,  directly 
caused  in  this  cruel  race  for  wealth,  and  in  ahuost  everv  case 
easily  preventable.  Yet  they  are  not  ])revented,  solely  be- 
cause to  do  so  would  somewhat  diminish  th(^  })rofits  of  the 
capitalists  and  legislators  who  are  directly  responsible  for  this 
almost  world-wide  defacement  and  destruction,  and  virtual 
massacre  of  the  ignorant  and  defenceless  workers. 

The  nineteenth  century  saw  the  rise,  the  development,  and 
the  culmination  of  these  crimes   against  God   and  man.     Let 


302  THE  WORLD  OF  LIFE 

us  hope  that  the  twentieth  century  will  see  the  rise  of  a  truer 
religion,  a  purer  Christianity;  that  the  conscience  of  our 
rulers  will  no  longer  permit  a  single  man,  woman,  or  child  to 
have  its  life  shortened  or  destroyed  by  any  preventable  cause, 
however  profitable  the  present  system  may  be  to  their  employ- 
ers; that  no  one  shall  be  allowed  to  accumulate  wealth  by  the 
labour  of  others  unless  and  until  every  labourer  shall  have  re- 
ceived sufficient,  not  only  for  a  bare  subsistence,  but  for  all  the 
reasonable  comforts  and  enjoyments  of  life,  including  ample 
recreation  and  provision  for  a  restful  and  happy  old  age. 
Briefly,  the  support  of  the  labourers  without  any  injury  to 
health  or  shortening  of  life  should  be  a  first  charge  upon  the 
products  of  labour.  Every  kind  of  labour  that  will  not  bear 
this  charge  is  immoral  and  is  unworthy  of  a  civilised  com- 
munity. 

The  Teaching  of  the  Geological  Record 

But  this  is  a  digression.  Let  us  now  return  to  a  consid- 
eration of  the  main  features  of  the  course  of  life-development. 

The  first  point  to  w^hich  our  attention  may  be  directed  is, 
that  the  necessary  dependence  of  animal  life  upon  vegetation 
is  the  cause  of  some  of  the  most  prominent  and  perhaps  the 
most  puzzling  features  of  the  early  life-world  as  presented  to 
us  by  the  geological  record.  In  the  Palaeozoic  age  we  already 
meet  with  a  very  abundant  and  very  varied  aquatic  life,  in 
which  all  the  great  classes  of  the  animal  kingdom  —  sponges, 
zoophytes,  echinoderms,  worms,  Mollusca,  and  vertebrates  — 
were  already  fully  differentiated  from  each  other  as  we  now 
find  them,  and  existed  in  considerable  variety  and  in  gi'eat 
numbers.  It  is  quite  possible  that  the  seas  and  oceans  of  those 
remote  ages  were  nearly  as  full  of  life  as  they  are  now,  though 
the  forms  of  life  were  less  varied  and  generally  of  a  lower  type. 
But,  at  the  same  time,  the  animal  life  of  the  land  was  very 
scanty,  the  only  vertebrates  that  occupied  it  being  a  few  Am- 
phibia and  archaic  reptiles.  There  were,  however,  a  consid- 
erable number  of  primitive  centipedes,  spiders,  Crustacea,  and 


EXTENSIONS  OF  DARWINISM  ;J03 

even  true  insects,  the  latter  having  already  become  specialised 
into  several  of  our  existing  orders.  All  these  occur  either  in 
the  Coal  formation  of  Europe  or  the  Devonian  rocks  of  North 
America,  which  seems  to  imply  that  when  land-vegetation  first 
began  to  cover  the  earth  a  very  long  period  elapsed  before  any 
correspondingly  abundant  animal  life  was  develo])ed ;  and  this 
W'as  what  we, should  expect,  because  it  would  be  necessary  for 
the  former  to  become  thoroughly  established  and  developed 
into  a  sufficient  variety  of  forms  well  adapted  to  all  the  dif- 
ferent conditions  of  soil  and  climate,  in  order  that  they  might 
be  able  to  resist  the  attacks  of  the  larger  plant-feeding  animals, 
as  well  as  the  myriads  of  insects  when  these  appeared.  So 
far  as  we  can  judge,  the  vegetable  kingdom  was  left  to  develop 
freely  during  the  enormous  series  of  ages  comprised  in  the 
Devonian,  Carboniferous,  and  Permian  formations,  to  which 
we  must  add  the  gap  between  the  latter  and  the  Triassic  —  the 
first  of  the  Secondary  formations.  By  that  time  the  whole 
earth  had  probably  become  more  or  less  forest-clad,  but  with 
vegetation  of  a  Ioav  type  mostly  allied  to  our  ferns  and  horse- 
tails, with  some  of  the  earliest  ancestral  forms  of  pines  and 
cycads. 

In  the  succeeding  Secondary  era  the  same  general  type  of 
vegetation  prevailed  till  near  its  close ;  but  it  was  then  every- 
where subject  to  the  attacks  of  large  plant-devouring  reptiles, 
and  under  this  new  environment  it  must  necessarilv  have 
started  on  new  lines  of  evolution  tending  towards  those  higher 
flowering  plants  which,  throughout  the  Tertiary  period,  be- 
came the  dominant  type  of  vegetation.  It  seems  probable  that 
throughout  the  ages  animal  and  vegetable  life  acted  and  re- 
acted on  each  other.  The  earliest  luxuriant  land-vegetation, 
that  which  formed  the  great  coal-fields  of  the  earth,  was 
probably  adapted  to  the  physical  environment  alone,  almost 
uninfluenced  by  the  scanty  animal  life.  Then  reptiles  and 
mammals  were  differentiated ;  but  the  former  increased  more 
rapidly,  being  perhaps  better  fitted  to  live  upon  the  early  vege- 
tation and  to  survive  in  the  heavy  carbonated  atmosphere.     This 


304  THE  WORLD  OF  LIFE 

in  turn  became  more  varied  and  better  adapted  to  resist  their 
attacks;  and  when  the  new  type  had  become  well  established  it 
quickly  replaced  the  earlier  forms ;  and  the  highly  specialised 
reptiles,  unable  to  obtain  sufficient  nourishment  from  it,  and 
being  also  subject  to  the  attacks  of  Camivora  of  increasing 
power,  and  perhaps  to  some  adverse  climatic  changes,  quickly 
disappeared.  Then  came  the  turn  of  the  Mammalia,  the  birds, 
and  the  more  specialised  insects,  which,  during  this  vast  period, 
had  been  slowly  developing  into  varied  but  always  rather 
diminutive  forms,  the  birds  and  mammals  feeding  probably 
on  insects,  roots,  and  seeds;  but,  in  proportion  as  the  reptiles 
disappeared,  they  were  ready  to  branch  out  in  various  direc- 
tions, occupying  the  many  places  in  nature  left  vacant  by  these 
animals,  and  thus  initiated  that  wonderfully  varied  mam- 
malian life  which  throughout  the  whole  Tertiary  period  occu- 
pied the  earth's  surface  as  completely,  and  almost  as  exclu- 
sively, as  the  reptiles  had  done  during  the  middle  ages  of  geo- 
logical time. 

The  reactions  of  insects  and  flowers  are  universally  ad- 
mitted, as  are  those  between  birds  and  fruits ;  but  the  broader 
aspect  of  this  reaction  between  animal  and  plant  life  as  a 
whole  has  not,  I  think,  received  much  attention.  It  does, 
however,  seem  to  throw  a  glimmer  of  light  on  the  very  puz- 
zling facts  of  the  vast  development  of  Secondary  reptilian 
life,  the  apparent  arrest  of  development  of  mammals  during 
the  whole  vast  period,  and  the  rapid  and  abundant  outgrowths 
of  the  higher  types  both  of  plants  and  of  Mammalia  in  the 
Tertiary  age. 

The  complete  metamorphosis,  broadly  speaking,  of  both 
plant  and  animal  life,  on  passing  from  the  former  to  the  lat- 
ter epoch,  is  most  startling.  Such  a  change  was,  however,  ab- 
solutely essential,  not  only  for  the  production  of  the  higher 
Mammalia  and  intellectual  man,  but  also  to  provide  for  the 
infinitely  varied  needs  of  man's  material,  moral,  and  aesthetic 
development.  The  immensely  varied  plant-group  of  phanero- 
gams has  served  to  unlock  for  his  service  the  myriad  potenti- 


EXTENSIONS  OF  DARWINISM  305 

alities  which  lay  hidden  in  protoplasm  —  the  mysterious 
physical  basis  of  all  life.  To  this  vast  series  of  herbs  and 
shrubs  and  forest-trees  he  owes  most  of  the  charms,  the  deli- 
cacies, and  the  refinements  of  his  existence  —  almost  all  his 
fruits,  most  of  his  scents  and  savours,  together  with  a  large 
part  of  the  delight  he  experiences  in  mountain  and  valley, 
forest,  copse,  and  flower-spangled  meadow,  whieli  everywhere 
adorn  his  earthly  dwelling-place. 

To  this  we  must  add  the  infinitely  varied  uses  to  man  of 
domestic  animals,  all  supplied  by  the  higher  Mammalia  or 
birds,  while  no  single  reptile  has  ever  occupied  or  seems  able 
to  occupy  the  same  place.  We  can  only  speculate  on  the  part 
these  have  played  in  man's  full  development,  but  it  must  have 
been  a  great  and  an  important  one.  The  caring  for  cattle  and 
sheep,  the  use  of  milk,  butter,  and  cheese,  and  the  weaving 
of  wool  and  preparation  of  leather,  must  have  all  tended  to 
raise  him  from  the  status  of  a  beast  of  prey  to  that  of  the 
civilised  being  to  whom  some  animals  at  all  events  became 
helpers  and  friends.  And  this  elevation  was  carried  a  step 
further  when  the  horse  and  the  dog  became  the  companions 
of  his  daily  life,  while  fowls,  pigeons,  and  various  singing- 
birds  added  new  pleasures  and  occupations  to  his  home.  That 
such  creatures  should  have  been  slowly  evolved  so  as  to  reach 
their  full  development  at  the  very  time  when  lie  became  able 
to  profit  by  them  must  surely  be  accepted  as  additional  evi- 
dence of  a  foreseeing  mind  which,  from  the  first  dawn  of  life 
in  the  vegetable  and  animal  cells,  so  directed  and  organised 
that  life,  in  all  its  myriad  forms,  as,  in  the  far-off  future,  to 
provide  all  that  was  most  essential  for  the  growth  and  develop- 
ment of  man's  spiritual  nature. 

In  furtherance  of  this  subject  it  would  be  necessary  to  put 
a  definite  bar  to  the  persistence  of  a  lower  type  which  might 
have  prevented  or  seriously  checked  the  development  of  the 
higher  forms  destined  to  succeed  them ;  and  this  seems  to  have 
been  done  in  the  case  of  the  ]^^esozoic  reptiles  by  endowing 
them  with   such   a   limited    amount  of  intelligent   vitalitv   as 


306  THE  WORLD  OF  LIFE 

would  not  lead  to  its  automatic  increase  under  the  stress  of  a 
long  course  of  development,  though  accompanied  by  continual 
change  of  conditions  and  enormous  increase  in  size.  Hence 
the  "  ridiculously  small  brains  "  (as  they  have  been  termed) 
of  these  huge  and  varied  animals.  We  may  learn  from  this 
phenomenon,  and  the  parallel  case  of  the  huge  Dinocerata 
among  the  Tertiary  mammals,  that  development  of  a  varied 
form  and  structure  through  the  struggle  for  existence  does  not 
necessarily  lead  to  an  increase  in  intelligence  or  in  the  size  and 
complexity  of  its  organ  the  brain,  as  has  been  generally  as- 
sumed to  be  the  case. 

If,  as  John  Hunter,  T.  H.  Huxley,  and  other  eminent 
thinkers  have  declared,  ''  life  is  the  cause,  not  the  consequence, 
of  organisation,''  so  we  may  believe  that  mind  is  the  cause, 
not  the  consequence,  of  brain  development.  The  first  implies 
that  there  is  a  cause  of  life  independent  of  the  organism 
through  which  it  is  manifested,  and  this  cause  must  itself  be 
persistent  —  eternal  —  life,  any  other  supposition  being  es- 
sentially unthinkable.  And  if  we  must  posit  an  eternal  Life 
as  the  cause  of  life,  we  must  equally  posit  an  eternal  Mind  as 
the  cause  of  mind.  And  once  accept  this  as  the  irreducible 
minimum  of  a  rational  belief  on  these  two  great  questions, 
then  the  whole  of  the  argument  in  this  volume  falls  into  logical 
sequence. 

Life  as  a  cause  of  organisation  is  as  clearly  manifested 
and  as  much  a  necessity  in  the  plant  as  in  the  animal;  but 
they  are  plainly  different  kinds  (or  degrees)  of  life.  So 
there  are  undoubtedly  different  degrees  and  probably  also  dif- 
ferent kinds  of  mind  in  various  grades  of  animal  life.  And 
as  the  life-giver  must  be  supposed  to  cause  the  due  amount 
and  kind  of  life  to  flow  or  be  dra^vn  into  each  organism,  from 
the  universe  of  life  in  which  it  lives,  so  the  mind-giver,  in  like 
manner,  enables  each  class  or  order  of  animals  to  obtain  the 
amount  of  mind  requisite  for  its  place  in  nature,  and  to  or- 
ganise a  brain  such  as  is  required  for  the  manifestation  of  that 
limited  amount  of  mind  and  no  more. 


EXTEIsrSIO:N^S  OF  DARWINISM  307 

Thus  and  thus  only,  as  it  seems  to  mo,  can  we  under- 
stand the  raison  d'  etre  of  these  small-brained  animals.  They 
were  outgi'owths  of  the  great  tree  of  life  for  a  temporary  pur- 
pose, to  keep  doA\Ti  the  coarser  vegetation,  to  supply  animal 
food  for  the  larger  Carnivora,  and  thus  give  time  for  higher 
forms  to  obtain  a  secure  foothold  and  a  sullicient  amount  of 
varied  form  and  structure,  from  which  they  could,  when  bet- 
ter conditions  prevailed,  at  once  start  on  those  wonderful  di- 
verging lines  of  advance  which  have  resulted  in  the  perfected 
and  glorious  life-world  in  the  midst  of  which  we  live,  or  ought 
to  live. 

This  view  of  the  purport,  the  meaning,  and  the  higher  func- 
tion of  the  gTcat  and  varied  life-world  brings  us  by  a  differ- 
ent route  to  what  many  of  our  better  thinkers  and  teachers 
have  tried  to  impress  upon  us  — •  that  our  great  cities  are  the 
"  wens,''  the  disease-products  of  humanity,  and  that  until  they 
are  abolished  there  can  be  no  approach  to  a  true  or  rational 
civilisation. 

This  was  the  teaching  of  that  true  and  far-seeing  child  of 
nature,  William  Cobbett;  it  is  the  teaching  of  all  our  greatest 
sanitarians ;  it  is  the  teaching  of  Nature  herself  in  the  com- 
parative rural  and  urban  death-rates.  Yet  we  have  no  legis- 
lator, no  minister,  who  will  determinedly  set  himself  to  put 
an  end  to  the  continued  growth  of  these  "  wens  " ;  which  are 
wholly  and  absolutely  evil.  I  will,  therefore,  take  this  oppor- 
tunity of  showing  how  it  can  be  done. 

There  is  much  talk  now  of  what  will  and  must  be  the 
growth  of  London  during  the  next  twenty  or  fifty  years ;  and 
of  the  necessity  of  bringing  water  from  Wales  to  su})])ly  the 
increased  pojjulation.  But  where  is  the  necessity  ?  Why  pro- 
vide for  a  population  which  need  never  have  existed,  and 
whose  coming  into  existence  will  be  an  evil  and  of  no  pos- 
sible use  to  any  human  beings  but  the  landowners  and  specu- 
lators, who  will  make  money  by  the  certain  injury  of  their 
fellow-citizens.  If  the  House  of  Commons  and  the  l>ondt»n 
County  Council  are  not  the  bond-slaves  of  the  landowners  and 


308  THE  WOELD  OF  LIFE 

speculators,  they  have  only  to  refuse  to  allow  any  further 
water-supply  to  be  provided  for  London  except  what  now  ex- 
ists, and  London  will  cease  to  grow.  Let  every  speculator  have 
to  provide  water  for  and  on  his  own  estate,  and  the  thing  will 
be  done  —  to  the  enormous  benefit  of  humanity. 

The  same  thing  can,  I  presume,  be  done  by  Parliament  for 
any  other  growing  town  or  city.  It  can  justly  say :  '^  When 
you  have  not  a  gallon  of  polluted  water  in  your  town,  and 
when  its  death-rate  is  brought  down  to  the  average  standard 
of  rural  areas,  we  will  reconsider  the  question  of  your  further 
growth.''  By  that  time,  probably,  there  will  be  no  public  de- 
mand for  enlarging  our  "  wens  ''  and  a  very  strong  and  stem, 
one  for  their  cure  or  their  abolition. 


/ 


CHAPTER  XIV 

BIRDS    AND    INSECTS  :       AS    PROOFS    OF    AN    OKGANISING    AND 

DIRECTIVE    LIFE-PRINCIPLE 

If  we  strip  a  bird  of  its  feathers  so  that  we  can  see  its  bodj- 
structure  as  it  really  is,  it  appears  as  the  most  ungainly  and 
misshapen  of  living  creatures ;  yet  there  is  hardly  a  bird  but 
in  its  natural  garment  is  pleasing  in  its  form  and  motions, 
while  a  large  majority  are  among  the  most  beautiful  in  shape 
and  proportions,  the  most  graceful  in  their  activities,  and  often 
the  most  exquisite  and  fascinating  of  all  the  higher  animals. 
The  fact  is,  that  the  feathers  are  not  merely  a  surface-clothing 
for  the  body  and  limbs,  as  is  the  hairy  covering  of  most  mam- 
mals, but  in  the  wing  and  tail-feathers  form  an  essential  part 
of  the  structure  of  each  species,  without  which  it  is  not  a  com- 
plete individual,  and  could  hardly  maintain  its  existence  for 
a  single  day.  The  whole  internal  structure  has  been  gradually 
built  up  in  strict  relation  to  this  covering,  so  that  every  part 
of  the  skeleton,  every  muscle,  and  the  whole  of  the  vascular 
system  for  blood-circulation  and  aeration  have  been  slowly 
modified  in  such  close  adaptation  to  the  whole  of  the  plumage 
that  a  bird  without  its  feathers  is  almost  as  helpless  as  a  mam- 
mal which  has  lost  its  limbs,  tail,  and  teeth. 

Although  birds  are  so  highly  organised  as  to  rival  mam- 
'  mals  in  intelligence,  while  they  surpass  them  in  activity  and 
in  their  high  body -temperature,  yet  they  owe  this  position  to 
an  extreme  retrogressive  specialisation  resulting  in  the  com- 
plete loss  of  the  teeth,  while  the  digits  of  the  fore  limb  are  re- 
duced to  three,  the  bones  of  which  are  more  or  less  united,  and, 
though  slightly  movable,  are  almost  entirely  hidden  under  tho 
skin. 

The  earliest  fossil  bird,  the  Arch^eopteryx,   bad  throe  ap- 

301) 


310  THE  WORLD  OE  LIFE 

parentlj  free  and  movable  digits  on  the  fore  limbs,  each  end- 
ing in  a  distinct  claw ;  while  the  two  bones  forming  the  fore- 
arm appear  to  have  been  also  free  and  movable,  so  that  the 
wing  must  have  been  much  less  compact  and  less  effective  for 
flight  than  in  modern  birds.  This  bird  was  about  as  large  as 
a  rook,  but  with  a  tail  of  twenty  vertebra',  each  about  half  an 
inch  long  and  bearing  a  pair  of  feathers,  each  four  inches  in 
length  and  half  an  inch  broad,  while  the  wing  feathers  were 
nearly  twice  as  long.  The  almost  complete  disappearance  of 
the  unwieldy  tail,  with  the  fusing  together  of  the  wing-bones, 
must  have  gone  on  continuously  from  that  epoch.  In  the 
Cretaceous  period  the  long  tail  has  disappeared,  and  the  wing- 
bones  are  much  more  like  those  of  living  birds;  but  the  jaws 
are  still  toothed.  In  the  early  Tertiary  deposits  bird-remains 
are  more  numerous,  and  some  of  the  chief  orders  of  modern 
birds  seem  to  have  existed,  while  a  little  later  modern  families 
and  genera  appear. 

The  important  point  for  our  consideration  here  is  that,  in 
the  very  earliest  of  the  birds  yet  discovered  which  still  re- 
tained several  reptilian  characteristics,  true  feathers,  both  of 
wings  and  tail,  are  so  clearly  shown  as  to  leave  no  doubt  of 
their  practical  identity  with  those  of  living  birds. 

It  is  therefore  evident  that  birds  with  feathers  began  to  be 
developed  as  early  as  (perhaps  even  earlier  than)  the  mem- 
branous-winged reptiles  (Pterodactyles),  and  that  these  two 
groups  of  flying  vertebrates  began  on  two  opposite  principles. 
The  birds  must  have  started  on  the  principle  of  condensation 
and  specialisation  of  the  fore  limb  exclusively  for  flight  by 
means  of  feathers ;  the  other  by  the  extension  of  one  reptilian 
digit  to  support  a  wing-membrane,  while  reserving  the  others 
probably  for  suspension,  as  in  the  case  of  the  thumb  of  the 
bats. 

The  Marvel  and  Mystery  of  Feathers 

Looking  at  it  as  a  whole,  the  bird's  wing  seems  to  me 
to  be,  of  all  the  mere  mechanical  organs  of  any  living  thing, 


PKOOIS  OJ^^  OKGANiSi^'G  Aili\D  311 

that  ^vhicli  most  clearly  implies  the  working  out  of  a  j^recon- 
ceived  design  in  a  new  and  apparently  most  complex  and  dilli- 
cult  manner,  yet  so  as  to  produce  a  marvellously  successful  re- 
sult. The  idea  worked  out  was  to  reduce  the  jointed  bony 
framework  of  the  wings  to  a  compact  minimum  of  size  and 
maximum  of  strength  in  proportion  to  the  muscular  power 
employed ;  to  enlarge  the  breastbone  so  as  to  give  room  for 
greatly  increased  power  of  pectoral  muscles;  and  to  construct 
that  part  of  the  wing  used  in  flight  in  sucli  a  manner  as  to 
combine  great  strength  with  extreme  lightness  and  the  most 
perfect  flexibility.  In  order  to  produce  this  more  perfect  in- 
strument for  flight  the  plan  of  a  continuous  membrane,  as  in 
the  flying  reptiles  (whose  origin  was  probably  contcm})ora- 
neous  with  that  of  the  earliest  birds)  and  flying  mammals,  to 
be  developed  at  a  much  later  period,  was  rejected,  and  its  placo 
was  taken  by  a  series  of  broad  overlapping  oars  or  vanes, 
formed  by  a  central  rib  of  extreme  strength,  elasticity,  and 
lightness,  with  a  web  on  each  side  made  up  of  myriads  of  parts 
or  outgrowth  so  wonderfully  attached  and  interlocked  as  to 
form  a  self-supporting,  highly  elastic  structure  of  almost  in- 
conceivable delicacy,  very  easily  pierced  or  ruptured  by  the 
impact  of  solid  substances,  yet  able  to  sustain  almost  any 
amount  of  air-pressure  without  injury.  And  even  when  any 
part  of  this  delicate  web  is  injured  by  separating  the  adjacent 
barbs  from  each  other,  they  are  so  wonderfully  constructed  that 
the  pressure  and  movement  of  other  feathers  over  them  causes 
them  to  unite  together  as  firmly  as  before ;  and  this  is  done 
not  by  any  process  of  gro^vth,  or  by  any  adhesive  exudation, 
but  by  the  mechanical  structure  of  the  delicate  hooked  lamelhn 
of  which  they  are  composed. 

The  two  illustrations  here  given  (Figs.  lOS,  lOD)  show  two 
of  the  adjacent  fibre-like  parts  (barbs)  of  which  the  web  of  a 
bird's  feather  is  composed,  and  which  are  most  clearly  shown 
in  the  wing-feathers.  Tlie  slender  barbs  or  ribs  of  which  the 
web  of  the  feather  is  made  up  can  be  best  understood  by  strip- 
ping off  a  portion  of  the  wel)  and  separating  two  of  the  barbs 


312 


THE  WOELD  OE  LIEE 


from  the  rest.  With  a  good  lens  the  structure  of  the  barbs, 
with  their  delicate  hooked  barbules  interlocking  with  the  bent- 
out  upper  margins  of  the  barbules  beneath  them,  can  be  seen, 
as  shown  in  the  view  and  section  here  given.     The  barbs   (B, 


Magnified  View  of  the  Barbs  and  Barbules  forming  the  Web  of  a  Bird's 

Wing-Feathers  (X  50). 


Fig.  108. — 'View  of  a  portion  of  two  adjacent  Barbs   (B,  B),  looking  from 
the  Shaft  towards  the  edge  of  the  Feather. 

bd,  distal  barbules;  bp,  proximal  barbules. 


Fig.  109. —  Oblique  Section  through  the  Proximal  Barbules  in  a  plane  par- 
allel to  the  Distal  Barbules  of  the  upper  Figure. 
Letters  as  above ;    1,    2,   3,   barbicels  and  hamuli   of  the  ventral   side   of  the   distal 
barbule;   4,  barbicels  of  the  dorsal  side  of  the  same,  without  hamuli. 

(From  Newton's  Dictionary  of  Birds.) 


B  in  the  figures)  are  elastic,  homj  plates  set  close  together  on 
each  side  of  the  midrib  of  the  feather,  and  pointing  obliquely 
outwards;  while  the  barbules  are  to  the  barbs  what  the  barbs 
are  to  the  feather  —  excessively  delicate  horny  plates,  which 


PKOors  OF  oega:xising  mind         313 

also  grow  obliquely  outwards  towards  the  tip  of  the  barb. 
Laterally  they  touch  each  other  with  smooth,  glossy  surfaces, 
which  are  almost  air-tight,  yet  allow  whatever  slight  motions 
that  may  be  required  during  use,  while  remaining  interlocked 
with  the  barbules  of  the  adjoining  barb  in  the  manner  just  de- 
scribed. They  are  the  essential  elements  of  the  feather,  on  which 
its  value  both  for  flight  and  as  a  protective  clothing  depends. 
Even  in  the  smallest  wing- feathers  they  are  probably  a  liundred 
thousand  in  number,  since  in  the  long  wing-feather  of  a  crane 
the  number  is  stated  by  Dr.  Hans  Gadow  to  be  more  than  a 
million. 

What  are  termed  the  "  contour-feathers "  are  those  that 
clothe  the  whole  body  and  limbs  of  a  bird  with  a  garment  of 
extreme  lightness  which  is  almost  comj^letely  impen-ious  to 
either  cold  or  heat.  These  feathers  vary  greatly  in  shape  on 
different  parts  of  the  body,  sometimes  forming  a  dense  velvety 
covering,  as  on  the  head  and  neck  of  many  species,  or  de- 
veloped into  endless  variety  of  ornament.  They  fit  and  overlap 
each  other  so  perfectly,  and  entangle  so  much  air  between 
them,  that  rarely  do  birds  suffer  from  cold,  except  when  un- 
able to  obtain  any  shelter  from  violent  storms  or  blizzards.  Yet, 
as  everv  sino'le  feather  is  movable  and  erectile,  the  whole  bodv 
can  be  freely  exposed  to  the  air  in  times  of  oppressive  heat,  or 
to  dry  the  feathers  rapidly  after  bathing  or  after  unusually 
heavy  rain. 

A  great  deal  has  been  written  on  the  mechanics  of  a  bird's 
flight,  as  dependent  on  the  form  and  curvature  of  the  feathers 
and  of  the  entire  wing,  the  powerful  muscular  arrangements, 
and  especially  the  perfection  of  the  adjustment  by  which  dur- 
ing the  rapid  do^vn-stroke  the  combined  feathers  constitute  a 
perfectly  air-tight,  exceedingly  strong,  yet  highly  elastic  in- 
strument for  flight ;  while  the  moment  the  upward  motion  be- 
gins the  feathers  all  turn  upon  their  axes  so  that  the  air  passes 
between  them  with  hardly  any  resistance,  and  when  they  again 
begin  the  down-stroke  close  up  nutomatically  as  air-tight  as 
before.     Thus  the  effective  down-strokes  follow  each  other  so 


314  THE  WOKLD  OE  LIFE 

rapidly  that,  together  with  the  support  given  by  the  hinder 
portion  of  the  wings  and  tail,  the  onward  motion  is  kept  up, 
and  the  strongest  flying  birds  exhibit  hardly  any  undulation  in 
the  course  they  are  pursuing.  But  very  little  is  said  about  the 
minute  structure  of  the  feathers  themselves,  which  are  what 
renders  perfect  flight  in  almost  every  change  of  conditions  a 
possibility  and  an  actually  achieved  result. 

But  there  is  a  further  difference  between  this  instrument 
of  flight  and  all  others  in  nature.  It  is  not,  except  during 
actual  growth,  a  part  of  the  living  organism,  but  a  mechanical 
instrument  which  the  organism  has  built  up,  and  which  then 
ceases  to  form  an  integral  portion  of  it  —  is,  in  fact,  dead  mat- 
ter. Hence,  in  no  part  of  the  fully  grown  feather  is  there 
any  blood  circulation  or  muscular  attachment,  except  as  re- 
gards the  base,  which  is  firmly  held  by  the  muscles  and  ten- 
dons of  the  rudimentary  hand  (fore  limb)  of  the  bird.  This 
beautiful  and  delicate  structure  is  therefore  subject  to  wear 
and  tear  and  to  accidental  injury,  but  probably  more  than  any- 
thing else  by  the  continuous  attrition  during  flight  of  dust- 
laden  air,  which,  by  wearing  away  the  more  delicate  parts 
of  the  barbules,  renders  them  less  able  to  fulfil  the  various 
purposes  of  flight,  of  body-clothing,  and  of  concealment,  as  well 
as  the  preservation  of  all  those  colours  and  markings  which  are 
especially  characteristic  of  each  species,  and  generally  of  each 
sex  separately,  and  which,  having  all  been  developed  under  the 
law  of  utility,  are  often  as  important  as  structural  characters. 
Provision  is  therefore  made  for  the  annual  renewal  of  every 
feather  by  the  process  called  moulting.  The  important  wing- 
feathers,  on  which  the  very  existence  of  most  birds  depends, 
are  discarded  successively  in  pairs  at  such  intervals  as  to  allow 
the  new  growth  to  be  Avell  advanced  before  the  next  pair  are 
thrown  off,  so  that  the  bird  never  loses  its  power  of  flight, 
though  this  may  be  somewhat  impaired  during  the  process. 
The  rest  of  the  plumage  is  replaced  somewhat  more  rapidly. 

This  regrowth  every  year  of  so  complex  and  important  a 
part  of  a  bird's  structure,  always  reproducing  in  every  feather 


PROOFS  OF  OEGAKISIKG  MIIS'J)  315 

the  size  and  shape  characteristic  of  the  species,  Avhile  each  of 
the  often  very  diverse  feathers  grows  in  its  right  place,  and  re- 
produces the  various  tints  and  colours  on  certain  parts  of  every 
feather  which  go  to  make  up  the  characteristic  colours,  markings, 
or  ornamental  plumes  of  each  species  of  bird,  presents  us  with 
the  most  remarkable  cases  of  heredity,  and  of  ever-present  ac- 
curately directed  growth-power,  to  be  found  in  the  whole  range 
of  organic  nature. 

The  Nature  of  Growth 

The  growth  of  every  species  of  organism  into  a  highly  com- 
plex form,  closely  resembling  one  or  other  of  its  parents,  is  so 
universal  a  fact  that,  \vith  most  people,  it  ceases  to  excite  won- 
der or  curiosity.  Yet  it  is  to  this  day  absolutely  inexplicable. 
No  doubt  an  immense  deal  has  been  discovered  of  the  mech- 
anism of  growth,  but  of  the  nature  of  the  forces  at  work,  or  of 
the  directive  agencies  that  guide  and  regulate  the  forces,  we 
have  nothing  but  the  vaguest  hints  and  conjectures.  All 
growth,  animal  or  vegetable,  has  been  long  since  ascertained  to 
begin  with  the  formation  and  division  of  cells.  A  cell  is  a 
minute  mass  of  protoplasm,  a  substance  held  to  be  the  physical 
basis  of  life.  This  is,  chemically,  the  most  complex  substance 
known,  for  while  it  consists  mainly  of  four  elements  —  car- 
bon, hydrogen,  nitrogen,  and  oxygen  —  it  is  now  ascertained 
that  eight  other  elements  are  always  present  in  cells  composed 
of  it  —  sulphur,  phosphorus,  chlorine,  potassium,  sodium, 
magnesium,  calcium,  and  iron.  Besides  these,  six  others  are 
occasionally  found,  but  are  not  essential  constituents  of  pro- 
toplasm. These  are  silicon,  fluorine,  bromine,  iodine,  alumi- 
nium, and  manganese.^ 

Protoplasm  is  so  complex  a  substance,  not  only  in  the  num- 
ber of  the  elements  it  contains,  but  also  in  the  mode  of  their 
chemical  combination,  that  it  is  quite  beyond  the  reach  of 
chemical  analysis.  It  has  been  divided  into  throe  groups  of 
chemical  substances  —  proteids,  carbohydrates,  and  fats.      The 

1  Verworu's  General  Physiology,  p.   100. 


316  THE  WOKLD  OF  LIFE 

first  is  always  present  in  cells,  and  consists  of  five  elements  — 
carbon,  hydrogen,  sulphur,  nitrogen,  and  oxygen.  The  two 
other  groups  of  organic  bodies,  carbohydrates  and  fats,  con- 
sist of  three  elements  only  —  carbon,  hydrogen,  and  oxygen,  the 
carbohydrates  forming  a  large  proportion  of  vegetable  products, 
the  fats  those  of  animals.  These  also  are  highly  complex  in 
their  chemical  structure,  but  being  products  rather  than  the 
essential  substance  of  living  things,  they  are  more  amenable 
to  chemical  research,  and  large  numbers  of  them,  including 
vegetable  and  animal  acids,  glycerin,  grape  sugar,  indigo, 
caifeine,  and  many  others,  have  been  produced  in  the  labora- 
tory, but  always  by  the  use  of  other  organic  products,  not  from 
the  simple  elements  used  by  nature. 

The  atomic  structure  of  the  proteids  is,  however,  so  wonder- 
fully complex  as  to  be  almost  impossible  of  determination. 
As  examples  of  recent  results,  haemoglobin,  the  red  colouring 
matter  of  the  blood,  was  found  by  Preyer  in  1866  to  be  as 
follows  — 

^eoo-tlgeo-^  154-'^  ^1^3^179? 

showing  a  total  of  1894  atoms,  while  Zinoffsky  in  1855  found 
the  same  substance  from  horse's  blood  to  be  — 

C'7i2-tiii3o-'^  214^245!'  6l^2> 

showing  a  total  of  2301  atoms.  Considering  the  very  small 
number  of  atoms  in  inorganic  compounds,  and  in  the  simpler 
vegetable  and  animal  products,  caffeine  containing  only  23 
(C7H7(CH3)N402),  the  complexity  of  the  proteids  will  be 
more  appreciated. 

Professor  Max  Verworu,  from  whose  gTeat  work  on  General 
Physiology  the  preceding  account  is  taken,  is  very  strong  in 
his  repudiation  of  the  idea  that  there  is  such  a  thing  as  a 
''  vital  force."  He  maintains  that  all  the  powers  of  life  reside 
in  the  cell,  and  therefore  in  the  protoplasm  of  which  the  cell 
consists.     But   he   recognises    a   great    difference   between   the 


PEOOFS  OF  OKGANISING  MIND  317 

dead  and  the  living  cell,  and  admits  that  our  knowledge  of  the 
latter  is  extremely  imperfect.  He  enumerates  many  differ- 
ences between  them,  and  declares  that  ''  substances  exist  in  liv- 
ing which  are  not  to  be  found  in  dead  cell-substance."  He 
also  recognises  the  constant  internal  motions  of  the  living  cell, 
the  incessant  waste  and  repair,  while  si  ill  preserving  the  highly 
complex  cell  in  its  integrity  for  indefinite  periods;  its  resist- 
ance during  life  to  destructive  agencies,  to  which  it  is  exposed 
the  moment  life  ceases ;  but  still  there  is  no  '"  vital  force  " — 
to  postulate  that  would  be  unscientific. 

Yet  in  this  highly  elaborate  volume  of  600  closely  printed 
pages,  dealing  with  every  aspect  of  cell-structure  and  physiol- 
ogy in  all  kinds  of  organisms,  he  gives  no  clue  whatever  to  the 
existence  of  any  directive  and  organising  powers  such  as  are 
absolutely  essential  to  preserve  even  the  unicellular  organism 
alive,  and  which  become  more  and  more  necessary  as  we  pass 
to  the  higher  animals  and  plants,  with  their  vast  complexity 
of  organs,  reproduced  in  every  successive  generation  from 
single  cells,  which  go  through  their  almost  infinitely  elaborate 
processes  of  cell-division  and  recomposition,  till  the  whole  vast 
complex  of  the  organic  machinery  ■ —  the  whole  body,  limbs, 
sense,  and  reproductive  organs  —  are  built  up  in  all  their  per- 
fection of  structure  and  co-ordination  of  parts,  such  as  char- 
acterises every  living  thing ! 

Let  us  now  recur  to  the  subject  that  has  led  to  this  digres- 
sion —  the  feathers  of  a  bird.  We  have  seen  that  a  full-gi'own 
wing-feather  may  consist  of  more  than  a  million  distinct  parts 
—  the  barbules,  which  give  the  feather  its  essential  character, 
whether  as  an  organ  of  flight  or  a  mere  covering  and  heat-pre- 
server of  the  body.  But  these  barbules  are  themselves  highly 
specialised  bodies  with  definite  forms  and  surface-texture, 
attaching  each  one  to  its  next  lateral  barbule,  and,  by  a  kind 
of  loose  hook-and-eye  formation,  to  those  of  the  succeeding 
barb.  Each  of  these  barbules  must  therefore  be  built  up  of 
many  thousands  of  cells  (probably  many  millions),  differing 
considerably  in  form  and  powers  of  cohesion,  in  order  to  pro- 


318  THE  WORLD  OE  LIFE 

cluce  the  exact  strength,  elasticity,  and  continuity  of  the  whole 
web. 

Now  each  feather  "  grows/'  as  we  say,  out  of  the  skin,  each 
one  from  a  small  group  of  cells,  which  must  be  formed  and 
nourished  by  the  blood,  and  is  reproduced  each  year  to  replace 
that  which  falls  away  at  moulting  time.  But  the  same  blood 
supplies  material  for  every  other  part  of  the  body  —  builds 
up  and  renews  the  muscles,  the  bones,  the  viscera,  the  skin, 
the  nerves,  the  brain.  What,  then,  is  the  selective  or  directing 
power  which  extracts  from  the  blood  at  every  point  where 
required  the  exact  constituents  to  form  here  bone-cells,  there 
muscle-cells,  there  again  feather-cells,  each  of  which  possesses 
such  totally  distinct  properties  ?  And  when  these  cells,  or 
rather,  perhaps,  the  complex  molecules  of  which  each  kind  of 
cell  is  formed,  are  separated  at  its  special  point,  w^hat  is  the 
constructive  power  wdiich  welds  them  together,  as  it  were,  in 
one  place  into  solid  bone,  in  another  into  contractile  muscle,  in 
another  into  the  extremely  light,  strong,  elastic  material  of  the 
feather  —  the  most  unique  and  marvellous  product  of  life  ? 
Yet  again,  wdiat  is  the  nature  of  the  power  which  deteiToines 
that  every  separate  feather  shall  always  "  grow  "  into  its  exact 
shape  ?  For  no  two  feathers  of  the  twenty  or  more  which 
form  each  wing,  or  those  of  the  tail,  or  even  of  the  thousands 
on  the  whole  body,  are  exactly  alike  (except  as  regards  the 
pairs  on  opposite  sides  of  the  body),  and  many  of  these  are 
modified  in  the  strangest  way  for  special  purposes.  Again, 
what  directive  a2:encv  determines  the  distribution  of  the  col- 
ouring  matter  (also  conveyed  by  the  blood)  so  that  each  feather 
shall  take  its  exact  share  in  the  production  of  the  whole  pattern 
and  colouring  of  the  bird,  which  is  immensely  varied,  yet 
always  symmetrical  as  a  whole,  and  has  always  a  purpose, 
either  of  concealment,  or  recognition,  or  sexual  attraction  in 
its  proper  time  and  place  ? 

Xow,  in  none  of  the  volumes  on  the  physiology  of  animals 
that  I  have  consulted  can  I  find  any  attempt  whatever  to 
grapple  Avith  this  fundamental  question  of  the  directive  power 


PROOFS  OF  ORGANISING  MIND      319 

that,  in  every  case,  first  secretes,  or  as  it  were  creates,  out  of 
the  protoplasm  of  the  blood,  special  molecules  adapted  for  the 
2:>roductiou  of  each  malcrial  —  bone,  muscle,  nerve,  skin,  hair, 
feather,  etc.  etc., —  carries  these  molecules  to  the  exact  part 
of  the  body  where  and  when  they  are  required,  and  brings  into 
play  the  complex  forces  that  alone  can  1)uild  up  with  (ri-eat 
rapidity  so  strangely  complex  a  structure  as  a  feather  adapted 
for  flight.  Of  course  the  difficulties  of  conceiving  how  this 
has  been  and  is  being  done  before  our  eyes  is  nearly  as  great 
in  the  case  of  any  other  specialised  part  of  the  animal  body; 
but  the  case  of  the  feathers  of  the  bird  is  unique  in  many  ways, 
and  has  the  advantage  of  being  wdiolly  external,  and  of  being 
familiar  to  every  one.  It  is  also  easily  accessible  for  examina- 
tion either  in  the  living  bird  or  in  the  detached  feather,  which 
latter  offers  wonderful  material  for  microscopic  examination 
and  study.  To  myself,  not  all  that  has  been  written  about 
the  properties  of  protoplasm  or  the  innate  forces  of  the  cell, 
neither  the  physiological  units  of  Herbert  Spencer,  the  pan- 
genesis hypothesis  of  Darwin,  nor  the  continuity  of  the  germ- 
plasm  of  Weismann,  throw  the  least  glimmer  of  light  on  this 
great  problem.  Each  of  them,  especially  the  last,  help  us  to 
realise  to  a  slight  extent  the  nature  and  laws  of  heredity,  but 
leave  the  great  problem  of  the  nature  of  the  forces  at  work  in 
growth  and  reproduction  as  mysterious  as  ever.  IModern 
physiologists  have  given  us  a  vast  body  of  information  on  the 
structure  of  the  cell,  on  the  extreme  complexity  of  the  proc- 
esses which  take  place  in  the  fertilised  ovum,  and  on  the  exact 
nature  of  the  successive  changes  up  to  the  stage  of  maturity. 
But  of  the  forces  at  work,  and  of  the  power  which  guides  those 
forces  in  building  up  the  whole  organ,  we  find  no  enlighten- 
ment.    They  will  not  even  admit  that  any  such  constructive 

guidance  is  required ! 
* 

A  Physiological  Allegory 

For   an   imaginary  parallel   to   this   state  of   tliinirs,   let   us 
suppose  some  race  of  intellia'cut   beings  wlio   have   tlie   j)Ower 


320  THE  WORLD  OF  LIFE 

to  visit  the  earth  and  see  what  is  going  on  there.  But  their 
faculties  are  of  such  a  nature  that,  though  they  have  perfect 
perception  of  all  inanimate  matter  and  of  plants,  they  are 
absolutely  unable  either  to  see,  hear,  or  touch  any  animal  living 
or  dead.  Such  beings  would  see  everywhere  matter  in  motion, 
but  no  apparent  cause  of  the  motion.  They  would  see  dead 
trees  on  the  ground,  and  living  trees  being  eaten  away  near 
the  base  by  axes  or  saws,  which  w^ould  appear  to  move  spon- 
taneously; they  would  see  these  trees  gradually  become  logs 
by  the  loss  of  all  their  limbs  and  branches,  then  move  about, 
travel  along  roads,  float  down  rivers,  come  to  curious  machines 
by  which  they  are  split  up  into  various  shapes ;  then  move 
away  to  where  some  great  structure  seems  to  be  growing  up, 
where  not  only  wood,  but  brick  and  stone  and  iron  and  glass 
in  an  infinite  variety  of  shapes,  also  move  about  and  ultimately 
seem  to  fix  themselves  in  certain  positions.  Special  students 
among  these  spirit-inquirers  would  then  devote  themselves  to 
follow  back  each  of  these  separate  materials  —  the  wood, 
the  iron,  the  glass,  the  stone,  the  mortar,  etc. —  to  their  sep- 
arate sources;  and,  after  years  thus  spent,  would  ultimately 
arrive  at  the  great  generalisation  that  all  came  primarily  out 
of  the  earth.  They  would  make  themselves  acquainted  with 
all  the  physical  and  chemical  forces,  and  would  endeavour  to 
explain  all  they  saw  by  recondite  actions  of  these  forces.  They 
would  argue  that  what  they  saw  was  due  to  the  forces  they 
had  traced  in  building  up  and  modifying  the  crust  of  the 
earth ;  and  to  those  who  pointed  to  the  result  of  all  this  ^'  mo- 
tion of  matter "  in  the  finished  product  —  the  church,  the 
mansion,  the  bridge,  the  railway,  the  huge  steamship  or  cotton 
factory  or  engineering  works  —  as  positive  evidence  of  design, 
of  directive  power,  of  an  unseen  and  unknown  mind  or  minds, 
they  would  exclaim,  "  You  are  wholly  unscientific ;  we  know 
the  physical  and  chemical  forces  at  work  in  this  curious  world, 
and  if  we  study  it  long  enough  we  shall  find  that  known  forces 
will  explain  it  all." 

If  we  suppose  that  all  the  smaller  objects,  even  if  of  the 


PEOOFS  OF  ORGANISING   MIXD  :]21 

same  size  as  ourselves,  enn  only  he  seen  by  microscopes,  and 
that  with  improved  instruments  the  various  tools  we  use,  as 
well  as  our  articles  of  furniture,  our  food,  and  our  tahlc-fit tings 
(knives  and  forks,  dishes,  glasses,  etc.,  and  even  our  watches, 
our  needles  and  pins,  etc.)  become  perceptible,  as  well  as  the 
food  and  drinks  which  are  seen  also  to  move  about  and  dis- 
appear; and  when  all  this  is  observed  to  recur  at  certain  def- 
inite intervals  every  day,  there  woidd  be  great  jubihition  over 
the  discovery,  and  it  would  be  loudly  proclaimed  that  with 
still  better  microscopes  -all  would  be  explained  in  terms  of 
matter  and  motion ! 

That  seems  to  me  very  like  the  position  of  modern  physiol- 
ogy in  regard  to  the  processes  of  the  growth  and  development 
of  living  things. 

Insects  and  their  Metamorphosis 

We  now  have  to  consider  that  vast  assemblage  of  small 
winged  organisms  constituting  the  class  Insect  a,  or  insects, 
which  may  be  briefly  defined  as  ringed  or  jointed  (annuluse) 
animals,  with  complex  mouth-organs,  six  legs,  and  one  or  two 
pairs  of  wings.  They  are  more  numerous  in  species,  and 
perhaps  also  in  individuals,  than  all  other  land-animals  put 
together;  and  in  either  their  larval  or  adult  condition  supi)ly 
so  large  and  important  a  part  of  the  food  of  birds,  that  the 
existence  of  the  latter,  in  the  variety  and  abundance  we  now 
behold,  may  be  said  to  depend  upon  the  former. 

The  most  highly  developed  and  the  most  abundant  of  the 
insect  tribes  are  those  which  possess  a  perfect  metamorphosis, 
that  is,  which  in  their  larval  state  are  the  most  comi)letely 
unlike  their  perfect  condition.  They  comprise  the  great  orders 
Lepidoptera  (butterflies  and  moths),  Coleojitera  (beetles), 
Hymenoptera  (bees,  ants,  etc.),  and  Diptc^-a  (two-winged 
flies),  the  first  and  last  being  those  which  are  perha])s  the  most 
important  as  bird-food.  In  all  these  orders  the  eggs  produce 
a  minute  aTub,  maggot,  or  caterpillar,  a-  they  are  variously 
called,  the  first  havino-  a  distinct  head  but  no  legs,  the  second 


322  THE  WORLD  OF  LIFE 

neither  head  nor  legs,  while  the  third  have  both  head  and  legs, 
and  are  also  variously  coloured,  and  often  possess  spines,  horns, 
hair-tufts,  or  other  appendages. 

Every  one  knows  that  a  caterpillar  is  almost   as  different 
from  a  butterfly  or  moth  in  all  its  external  and  most  of  its 
internal  characters,   as  it  is  possible  for  any  two  animals  of 
the   same   class   to   be.     The   former  has   six   short   feet   with 
claws  and  ten  fleshy  claspers;  the  latter,  six  legs,  five- jointed, 
and  with  subdivided  tarsi;  the  foi-mer  has  simple  eyes,  biting 
jaws,  and  no  sign  of  wings;  the  latter,  large  compound  eyes, 
a  spiral  suctorial  mouth,  and  usually  four  large  and  beauti- 
fully coloured  wrings.     Internally  the  whole  muscular  system 
is  quite  different  in  the  two  forms,  as  well  as  the  digestive 
organs,   while   the   reproductive   parts   are   fully   developed   in 
the  latter  only.     The  transformation  of  the  larva  into  the  per- 
fect insect  through  an  intervening  quiescent  pupa  or  chrysalis 
stage,  lasting  from  a  few  days  to  several  months  or  even  years, 
is  substantially  the  same  process  in  all  the  orders  of  the  higher 
insects,  and  it  is  certainly  one  of  the  most  marvellous  in  the 
whole  organic  world.     The  untiring  researches  of  modern  ob- 
servers, aided  by  the  most  perfect  microscopes   and  elaborate 
methods  of  preparation  and  observation,  have  revealed  to  us 
the  successive  stages  of  the  entire  metamorphosis,   which  has 
thus  become  more  intelligible  as  to  the  method  or  succession 
of  stages  by  which  the  transformation  has  been  effected,  though 
leaving  the  fundamental  causes  of  the  entire  process  as  mys- 
terious  as   before.     Years   of  continuous   research  have   been 
devoted  to  the  subject,  and  volumes  have-  been  Avritten  upon  it. 
One  of  the  most  recent  English  writers  is  Mr.  B.   Thompson 
Lowne,  F.E.C.S.,  who  has  devoted  about  a  quarter  of  a  cen- 
tury to  the  study  of  one  insect  —  the  common  blow-fly  —  on 
the   anatomy,   physiology,   and   development   of  w^hich   he   has 
published  an  elaborate  work  in  two  volumes  dealing  with  every 
part  of  the  subject.     He  considers  the  two-winged  flies  to  be 
the  highest  development  of  the  insect-type ;   and  though  they 
have  not  been  so  popular  among  entomologists  as  the  Coleoptera 


PEOOFS  OF  ORGAXISLXG  MLXl) 


and  Lepidoptera,  he  believes  them  to  be  the  most  nnmenjus  in 
species  of  all  the  orders  of  insects.  1  will  now  endeavour  to 
state  in  the  fewest  words  possible  tbe  general  results  of  his 
studies,  as  well  as  those  of  the  students  of  the  other  orders 
mentioned,   which   are   all   in   substantial   agreement. 

In  those  insects  which  have  the  least  comi)lete  metamorpho- 
sis —  the  cockroaches  —  the  young  emerge  from  the  egg  with 
the  same  general  form  as  the  adult,  but  with  rudimentarv 
wings,  the  perfect  wrings  being  acquired  after  a  succession  of 
moults.  These  seem  to  be  the  oldest  of  all  insects,  fossilised 
remains  of  a  similar  type  being  found  in  the  Silurian  forma- 
tion. Locusts  and  Hemiptera  are  a  little  more  advanced,  and 
are  less  ancient  geologically.  Between  these  and  the  four 
orders  with  complete  metamorphosis  there  is  a  great  gap,  which 
is  not  yet  bridged  over  by  fossil  forms.  But  from  a  minute 
study  of  the  development  of  the  egg,  which  has  been  examined 
almost  hour  by  hour  from  the  time  of  its  fertilisation,  the 
conclusion  has  been  reached,  that  the  great  difference  we  now 
see  between  the  larva  and  imago  (or  perfect  insect)  has  been 
brought  about  by  a  double  process,  simultaneously  going  on, 
of  progression  and  retrogression.  Starting  from  a  form  some- 
what resembling  the  cockroach,  but  even  lower  in  the  scale  of 
organisation,  the  earlier  stages  of  life  have  become  more  sim- 
plified, and  more  adapted  (in  the  case  of  Lepidoptera)  for 
converting  living  tissues  of  plants  into  animal  protoplasm,  thus 
laying  up  a  store  of  matter  and  energy  for  the  development 
of  the  perfect  insect ;  wdiile  the  latter  form  has  become  so  fully 
developed  as  to  be  almost  independent  of  food-supply,  by  being 
ready  to  carry  out  the  functions  of  reproduction  within  a  few 
days  or  even  hours  of  its  emergence  from  the  pupa  case. 

At  first  this  retrogression  of  the  first  stage  of  growth  towards 
a  simple  feeding  machine  took  place  at  the  period  of  the  suc- 
cessive moults,  but  it  being  more  advantageous  to  hav(^  the 
larva  stage  wholly  in  the  form  best  adaptcMl  for  the  storing  up 
of  living  protoplasm,  the  retrogressive  variations  became  stop 
by  step   earlier,   and   at  length   occurred   within   the   egg.     At 


324  THE  WOELD  OF  LIFE 

this  early  period  certain  rudiments  of  wings  and  other  organs 
are  represented  by  small  groups  of  minute  cells  termed  by 
Weismann  imaginal  discs,  which  were  determined  by  him  to 
be  the  rudiments  of  the  perfect  insect.  These  persist  un- 
changed through  the  whole  of  the  active  larval  stage ;  but  as 
soon  as  the  final  rest  occurs  preliminary  to  the  last  moult,  a 
most  wonderful  process  commences.  The  whole  of  the  internal 
organs  of  the  larva  —  muscles,  intestines,  nerves,  respiratory 
tubes,  etc. — ■  are  gradually  dissolved  into  a  creamy  pulp ;  and 
it  has  further  been  discovered  that  this  is  effected  through  the 
agency  of  white  blood-corpuscles  or  phagocytes,  which  enter 
into  the  tissues,  absorb  them,  and  transform  them  into  the 
creamy  pulp  referred  to.  This  mass  of  nutritive  pulp  thence- 
forth serves  to  nourish  the  rapidly  growing  mature  insect,  with 
all  its  wonderful  complication  of  organs  adapted  to  an  entirely 
new  mode  of  life. 

There  is,  I  believe,  nothing  like  this  complete  decomposi- 
tion of  one  kind  of  animal  structure  and  the  regrowth  out  of 
this  broken-down  material  —  which  has  thus  undergone  decom- 
position of  the  cells,  but  not  apparently  of  the  protoplasmic 
molecules  —  to  be  found  elsewhere  in  the  whole  course  of 
organic  evolution;  and  it  introduced  new  and  tremendous  dif- 
ficulties into  any  mechanical  or  chemical  theory  of  growth  and 
of  hereditary  transmission.  We  are  forced  to  suppose  that  the 
initial  stages  of  every  part  of  the  perfect  insects  in  all  their 
wonderful  complexity  and  diversity  of  structure  are  formed 
in  the  egg,  and  that  during  the  subsequent  raj^idly  growing 
development  of  the  larva  they  remain  dormant ;  then,  that  the 
whole  structure  of  the  fully  grown  larva  is  resolved  into  its 
constituent  molecules  of  living  protoplasm,  still  without  the 
slightest  disturbance  of  the  rudimentary  germs  of  the  perfect 
insect,  which  at  a  special  moment  begin  a  rapid  course  of  de- 
velopmental growth.  This  growth  has  been  followed,  step  by 
step  through  all  its  complicated  details,  by  ^Ir.  Lowne  and 
many  other  enthusiastic  workers ,  but  I  will  call  attention  here 


PEOOFS  OF  ORGANISING  AilXD  325 

only  to  the  special  case  of  the  Lepidoptera,  l)ocnu>c  these  are 
far  more  popuLarly  known,  and  the  special  feature  which  dis- 
tinguishes them  from  most  other  insects  is  fauiiliar  to  every 
one,  and  can  be  examined  by  means  of  a  good  pocket  lens  or 
microscope  of  moderate  power.  I  allude,  of  course,  !<•  the 
•wonderful  scales  Avhich  clothe  the  wings  of  most  buttcrllics 
and  moths,  and  which  produce  the  brilliant  colours  and  in- 
finitely varied  patterns  with  which  they  are  adorned.  (){' 
conrse,  the  still  more  extensive  order  of  the  C(deoptera 
(beetles)  present  a  similar  phenomenon  in  the  cuh^urs  and 
markings  of  their  wing-cases  or  elytra,  and  what  is  said  of 
the  one  order  will  apply  broadly  to  the  other. 

The  wings  of  butterflies  can  be  detected  in  very  young 
caterpillars  when  they  are  only  one-sixth  of  an  inch  long,  as 
small  out-foldings  of  the  inner  skin,  which  remain  unchanged 
while  the  larva  is  growing;  but  at  the  chrysalis  (or  pupa)  stage 
the  wings  ex^iand  to  about  sixty  times  their  former  area,  and 
the  two  layers  of  cells  composing  them  then  become  visible. 
At  this  time  they  are  as  transparent  as  glass ;  but  two  ur  three 
weeks  before  emergence  of  the  imago  they  become  opaque  white, 
and  a  little  later  dull  yellow'  or  drab;  twenty-four  hours  later 
the  true  colours  begin  to  appear  at  the  centre  of  each  wing. 
It  is  during  the  transparent  stage  that  the  scales  begin  tf>  Ix* 
formed  as  minute,  bag-like  sacks  filled  with  protoplasm ;  the 
succeeding  whiteness  is  caused  by  the  protoplasm  being  with- 
drawn and  the  sacks  becoming  filled  with  air.  The  pupal 
blood  then  enters  them,  and  from  this  the  colouring  matter  is 
secreted.  The  scales  are  formed  in  parallel  lines  along  ridges 
of  the  corrugated  wing  membrane.  The  more  bfilliani  enloui-s 
seem  to  be  produced  from  the  dull  yellow  ]ugment  by  cheinical 
chanc'es  Avhich  occur  within  the  scales.  A  few  davs  belore 
emergence  the  scales  become  fullv  jxrown,  as  hii^hlv  coniph.'X 
structures  formed  of  parallel  rows  of  minute  cells,  each  -cale 
with  a  basal  stem  which  enters  a  pocket  of  the  skin  or  mem- 
brane, which  pockets  send   out   root^  wlii(^h   seem  to  penetrate 


326  THE  WOKLD  OF  LIFE 

through  the  skin.^  Another  complication  is  the  fact  that  the 
wonderful  metallic  colours  of  so  many  butterflies  are  not  caused 
by  pigments,  but  are  ^'  interference  colours  "  produced  by  fine 
striae  on  the  surface  of  the  scales.  Of  course,  where  eye-spots, 
fine  lines,  or  delicate  shadings  adorn  the  wings,  each  scale  must 
have  its  own  special  colour,  something  like  each  small  block 
in  a  mosaic  picture. 

As  this  almost  overwhelming  series  of  changing  events  passes 
before  the  imagination,  we  see,  as  it  were,  the  gradual  but 
perfectly  orderly  construction  of  a  living  machine,  which  at 
first  appears  to  exist  for  the  sole  purpose  of  devouring  leaves 
and  building  up  its  own  wonderful  and  often  beautiful  body, 
thereby  changing  a  lower  into  a  higher  form  of  protoplasm. 
Its  limbs,  its  motions,  its  senses,  its  internal  structure,  are  all 
adapted  to  this  one  end.  Wlien  fully  grown  it  ceases  to  feed, 
prepares  itself  for  the  great  change  by  various  modes  of  con- 
cealment —  in  a  cocoon,  in  the  earth,  by  suspension  against 
objects  of  similar  colours,  or  which  it  becomes  coloured  to 
imitate  —  rests  awhile,  casts  its  final  skin,  and  becomes  a 
pupa.  Then  follows  the  great  transformation  scene,  as  in  the 
blow-fly.  All  the  internal  organs  which  have  so  far  enabled 
it  to  live  and  grow  —  in  fact,  the  whole  body  it  has  built  up, 
with  the  exception  of  a  few  microscopic  groups  of  cells  —  be- 
come rapidly  decomposed  into  its  physiological  elements,  a 
structureless,  creamy  but  still  living  protoplasm ;  and  when 
this  is  completed,  usually  in  a  few  days,  there  begins  at  once 
the  building  up  of  a  new,  a  perfectly  different,  and  a  much 
more  highly  organised  creature  both  externally  and  internally 
—  a  creature  comparable  in  organisation  with  the  bird  itself, 
for  which,  as  we  have  seen,  it  appears  to  exist.  And,  in  the 
case  of  the  Lepidoptera,  the  wings,  far  simpler  in  construc- 
tion than  those  of  the  bird,  but  apparently  quite  as  well  adapted 
to  its  needs,  develop  a  more  or  less  complete  covering  of  minute 

1  This  description  is  from  Mr.  A.  G.  Mayer's  paper  on  the  Development 
of  the  Wing  Scales  of  Butterflies  and  Moths  (Bull.  Mus.  Comp.  Zool.  Harv. 
Coll.,  June  1896),  so  far  as  I  can  give  it  in  a  verv  condensed  abstract. 


PEOOFS  OF  OKGA.XISIXG  Ail.XD  327 

scales,  whose  chief  or  only  function  aijpears  tu  be  tu  paint 
them  with  all  the  colours  and  all  tlie  glittering  reflections  of 
the  animal,  the  vegetable,  and  the  mineral  kingdoms,  to  an 
equal  if  not  a  greater  extent  than  in  the  case  of  the  birds  them- 
selves. The  butterflies,  or  diurnal  Le])idoi)tera  alone,  not  only 
present  us  with  a  range  of  colour  and  pattern  and  of  metallic 
brilliancy  fully  equal  (probably  superior),  to  that  of  l)irds, 
but  they  possess  also  in  a  few  cases  and  in  distinct  families, 
changeable  opalescent  hues,  in  which  a  pure  crimson,  or  blue, 
or  yellow  pigment,  as  the  incidence  of  light  varies,  changes 
into  an  intense  luminous  opalescence,  sometimes  resembling  a 
brilliant  phosphorescence  more  than  any  metallic  or  mineral 
lustre,  as  described  in  the  next  chapter. 

And  what  renders  the  wealth  of  coloration  thus  produced 
the  more  remarkable  is,  that,  unlike  the  feathers  of  birds,  tlic 
special  organs  upon  which  these  colours  and  patterns  are  dis- 
played are  not  functionally  essential  to  the  insect's  existence. 
They  have  all  the  appearance  of  an  added  superstructure  to 
the  wing,  because  in  this  way  a  greater  and  more  brilliant 
display  of  colour  could  be  produced  than  even  upon  the  ex- 
quisite plumage  of  birds.  It  is  true  that  in  some  cases,  these 
scales  have  been  modified  into  scent-a'lands  in  the  males  of 
some  butterflies,  and  perhaps  in  the  females  of  some  moths, 
but  otherwise  they  are  the  vehicles  of  colour  alone;  and  though 
the  diversity  of  tint  and  pattern  is  undoubtedly  useful  in  a 
variety  of  ways  to  the  insects  themselves,  yet  it  is  so  almost 
wholly  in  relation  to  higher  animals  and  not  to  their  own  kind, 
as  I  have  already  explained  in  Cluipter  IX.  It  is  generally 
admitted  that  insects  with  compound  eyes  possess  imperfect 
vision,  and  their  actions  seem  to  show  that  they  take  little 
notice  of  distant  objects,  except  of  lights  at  night,  and  only 
perceive  distinctly  what  is  a  few  inches  or  a  few  feet  from 
them;  while  there  is  no  proof  tliat  they  recognise  what  we  term 
colour  unless  as  a  greater  or  less  amount  of  light. 

But  as  regards  the  effect  of  the  shading  and  coloration  of 
insects  upon  the  higher  animals,  who  are  ahuo^t  always  their 


328  THE  WOELD  OF  LIFE 

enemies,  there  is  ample  evidence.  Almost  all  students  of  the 
subject  admit  that  the  markings  and  tints  of  insects  often 
resemble  their  environment  in  a  remarkable  manner,  and  that 
this  resemblance  is  protective.  The  eye-like  markings,  either 
on  the  upper  or  under  surfaces,  are  often  seen  to  be  imitations 
of  the  eyes  of  vertebrates,  when  the  insect  is  at  rest,  and  this 
also  is  protective.  The  brilliant  metallic  or  phosphorescent 
colours  on  the  wings  of  butterflies  may  serve  to  distract  ene- 
mies from  attacking  a  vital  part,  or,  in  the  smaller  species 
may  alarm  the  enemy  by  its  sudden  flash  with  change  of  posi- 
tion. But  while  the  colours  are  undoubtedly  useful,  the  mode 
of  producing  them  seems  unnecessarily  elaborate,  and  adds  a 
fresh  complication  in  the  way  of  any  mechanical  or  chemical 
conception  of  their  production. 


CHAPTER  XV 

GENEBAL  ADAPTATIONS  OF  PLANTS,  ANIMAI.S,  AND  MAN 

The  adaptations  of  plants  and  animals,  more  especially  as 
regards  the  cross-fertilisation  of  flowers  by  insects,  forms  a 
very  important  part  of  Darwin's  work,  and  has  been  fully 
and  popularly  elaborated  since  by  Grant  Allen,  Sir  John  Lub- 
bock (now  Lord  Avebury),  Hermann  ^1  tiller,  and  many  other 
writers.  I  have  also  myself  given  a  general  account  of  the 
whole  subject  both  in  my  Tropical  Xature,  and  my  Darwin- 
ism; but  as  there  are  some  points  of  importance  which,  1  be- 
lieve, have  not  yet  been  discussed,  and  as  the  readers  of  this 
volume  may  not  be  acquainted  with  the  vast  extent  of  the  evi- 
dence, I  will  here  give  a  short  outline  of  the  facts  before 
showing  how  it  bears  upon  the  main  argument  of  the  present 
work. 

Another  reason  why  it  is  necessary  to  recapitulate  the  evi- 
dence is  that  those  w^hose  knowledge  of  this  subject  is  derived 
from  having  read  the  Origin  of  Species  only,  can  have  no 
idea  whatever  of  the  vast  mass  of  observations  the  author  of 
that  work  had  even  then  collected  on  the  subject,  but  found 
it  impossible  to  include  in  it.  He  there  only  made  a  few 
general,  and  often  hypothetical,  references  both  to  the  facts 
of  insect- fertilisation,  and  to  the  purpose  of  cross-fertilisation. 
On  the  latter  point  he  makes  this  general  statement:  "  1  have 
come  to  this  conclusion  (that  flowers  are  coloured  to  attract 
insects)  from  finding  it  an  invariable  rule  that  when  a  flower 
is  fertilised  bv  the  wind  it  never  has  a  ciailv-coloured  ('or«)lla.'' 
Then  a  few  lines  farther  on  he  advei'ts  to  beautifullv  coloured 
fruits  and  says:  "But  the  beauty  servers  merely  as  a  guide  to 
birds  and  beasts,  in  order  tliat  the  fruit  may  be  devoured  and 
the  matured  seed  disseminated:  T  infer  that   this  is  the  case 

"■20 


330  THE  WORLD  OF  LIFE 

from  having  as  yet  found  no  exception  to  the  rule  that  seeds 
are  always  thus  disseminated  when  embedded  within  a  fruit 
of  any  kind  if  it  be  coloured  of  any  brilliant  tint."  ^ 

Such  general  statements  as  those  here  quoted  do  not  make 
much  impression.  The  astonishment  and  delight  of  botanists 
and  plant-lovers  can,  therefore,  be  imagined  when,  a  few  years 
later,  by  his  book  on  the  Fertilisation  of  Orchids  by  Insects, 
and  his  papers  on  the  Different  Forms  of  Flowers  in  the  prim- 
rose, flax,  lythrum,  and  some  others ;  he  opened  up  a  vast  new 
world  of  wonder  and  instruction  which  had  hitherto  remained 
almost  unnoticed.  These  were  followed  up  by  his  volumes 
on  The  Effects  of  Cross-  and  Self -Fertilisation  (in  1876), 
and  by  that  on  Different  Forms  of  Flowers  on  Plants  of  the 
same  Species  (in  1877)  giving  the  result  of  hundreds  of  care- 
ful experiments  made  by  himself  during  many  years,  serv'ing 
as  the  justification  for  the  few  general  observations  as  regards 
flowers  and  insects,  which  form  the  only  reference  to  the  sub- 
ject in  the  Origin  of  Species. 

The  facts  now  admitted  to  be  established  by  these  various 
researches  are:  (1)  that  crosses  between  different  individuals 
of  the  same  species,  either  constantly  or  occasionally,  are  ben- 
eficial to  the  species  by  increasing  seed-production  and  vigour 
of  growth;  (2)  that  there  are  innumerable  adaptations  in 
flowers  to  secure  or  facilitate  this  cross-fertilisation;  (3)  that 
all  irregular  flowers  —  Papilionacese,  Labiates,  Schrophulari- 
acese,  Orchidese,  and  others  —  have  become  thus  shaped  to  facil- 
itate cross-fertilisation.  Darwin's  general  conclusion,  that 
"  nature  abhors  perpetual  self-fertilisation,"  has  been  much 
criticised,  but  chiefly  by  writers  who  have  overlooked  the  term 
"  perpetual."  He  has  also  shown  how  the  wonderful  variety 
in  form  and  structure,  and  the  beauty  or  conspicuousness  of 
the  colours  of  flowers,  can  all  be  readily  explained,  on  this 
theory,  through  the  agency  of  variation  and  natural  selection, 
while  by  no  other  theory  is  any  real  and  effective  explanation 
possible.     But   besides   these   there   are   very  numerous   other 

1  Origin  of  Species,  6th  edition,  p.  161. 


GEXEKAL  ADAPTATIOXS  331 

adaptations  in  flowers  to  secure  them  from  injurious  insects 
or  from  the  effects  of  rain  or  wind  in  damaging  the  pollen 
or  the  stigmas,  as  beautifully  shown  in  Kerncr's  very  inter- 
esting volume  on  Flowers  and  their  Unhidden  Guests  —  a 
book  that  forms  an  admirable  sequel  to  Darwin's  works,  and 
is  equally  instructive  and  interesting. 

Of  late  years  writers  wdio  are  very  imperfectly  acquainted 
wdth  the  facts  proclaim  loudly  that  Darwin's  views  are  dis- 
proved, on  account  of  some  apparent  exceptions  to  the  general 
conclusions  he  has  reached.  Two  of  these  mav  he  here  noticed 
as  illustrative  of  the  kind  of  opposition  to  which  Darwinism 
is  exposed.  The  bee-orchis  of  our  chalky  downs,  though  con- 
spicuously coloured  and  with  a  fully-developed  labellum,  like 
the  majority  of  its  allies  wdiich  are  cross-fertilised  by  insects, 
yet  fertilises  itself  and  is  never  visited  by  insects.  This  has 
been  held  to  show  that  Darwin's  views  must  be  erroneous, 
notwithstanding  the  enormous  mass  of  evidence  on  which  they 
are  founded.  But  a  further  consideration  of  the  facts  shows 
that  they  are  all  in  his  favour.  In  the  south  of  Europe,  while 
the  bee-orchis  is  self-fertilised  as  in  England,  several  allied 
species  are  insect-fertilised,  bnt  they  rarely  produce  so  many 
seed-capsules  as  ours;  but,  strange  to  say,  an  allied  species 
(OpJirys  scolopax)  is  in  one  district  fertilised  by  insects  only, 
while  in  another  it  is  self-fertilised.  Again,  in  Portugal, 
w^here  many  species  of  Ophrys  are  found,  very  few  of  the 
flowers  are  fertilised  and  very  few  ripe  seed-ca])snles  are  pro- 
duced. But  owing  to  the  great  number  of  seeds  in  a  eapsuU', 
and  their  easy  dispersal  by  wind,  the  plants  are  ahnn(hint. 
These  and  many  other  facts  show  that  tor  some  unknown 
cause,  orchises  which  are  exclusively  insect-fertilised,  are  liable 
to  remain  unfertilised,  and  when  that  is  the  rase  it  becomes 
advantageous  to  the  species  to  be  able  to  f(M*tilise  itself,  and 
this  has  occurred,  partially  in  many  species,  and  (•(•mpletely 
in  our  bee-orchis. 

I  may  remark  here  llint  lhe  name  "  l>ee-orchis  "  Is  mislead- 
ing, as  the  flower  does  nol   resemble  any  of  our  bee-.      But  the 


332  THE  WORLD  OE  LIFE 

very  closely  allied  '^  spider  orchises  "  resemble  spiders  mucli 
more  closely.  It  occurs  to  me,  therefore,  that  the  general 
resemblance  to  bee  or  spider  may  occasionally  prevent  the 
flowers  being  eaten  off  by  sheep  or  lambs,  to  Avhom  even  spiders 
on  their  noses  or  lips  would  be  disagreeable. 

Mr.  Henry  O.  Forbes  observed,  in  Sumatra,  that  many  trop- 
ical orchids  with  show^y  flowers,  wdiich  were  perfectly  adapted 
for  insect-fertilisation,  yet  produced  very  few  seed-capsules, 
and  in  many  cases  none.  Yet  the  great  abundance  of  seeds, 
as  fine  as  dust,  in  a  single  capsule,  together  with  the  long  life 
of  most  orchids,  is  quite  sufficient,  in  most  cases,  to  preserve 
the  various  species  in  considerable  abundance.  When,  how- 
ever, there  is  any  danger  of  extinction  the  great  variability  of 
orchids,  which  at  first  enabled  them  to  become  so  highly  spe- 
cialised for  insect-fertilisation,  also  enables  them  (in  some 
cases)  to  return  to  self-fertilisation  as  in  our  bee-orchis. 
Should  this  continuous  self -fertilisation  at  length  lead  to  a  weak 
constitution,  then,  occasional  variations  serving  to  attract  in- 
sects by  nectar  or  in  other  ways,  with  minute  alterations  of 
structure  may  again  lead  to  fertilisation  by  insects. 

The  other  popular  objection  recently  made  to  Darwin's  views 
on  the  origin  of  the  flowers  is,  that  the  colours  and  shapes  of 
flowers  are  often  such  as  to  deter  herbivorous  animals  from 
eati-ng  them,  and  that  this  is  the  main  or  the  only  reason  why 
flowers  are  so  conspicuous.  The  special  case  supposed  to  prove 
this  is  that  some  buttercups  are  not  eaten  by  cattle  because 
they  are  acrid  or  poisonous,  and  that  the  bright  yellow  colour 
is  a  warning  of  inedibility. 

Even  if  these  statements  were  wdiolly  correct  they  would  not 
in  the  least  affect  the  general  proposition  that  all  conspicuous 
flowers  attract  insects  which  do  actually  cross-fertilise  them. 
But,  in  the  first  place,  there  is  much  difference  of  opinion  as 
to  the  inedibility  of  buttercups  by  cattle;  and,  in  the  second, 
our  three  most  common  yellow  buttercups  (Banunculus  acris, 
R.  repens,  and  R.  huJhosus)  are  so  constructed  that  they  can 
be  cross-fertilised  by  a  great  variety  of  insects,  and  as  a  mat- 


GENERAL  ADAPTATIONS 


O  '>  o 


ter  of  fact  are  so  fertilised.  IT.  Miillcr  grouped  those  lliroe 
species  together,  as  the  same  insects  visit  them  all,  and  lie 
found  that  thej  were  attractive  to  no  less  than  sixty  diilerent 
species,  including  23  flies,  11  beetles,  2-1  bees,  wasps,  etc.,  and 
5  butterflies. 

Any  readers  who  are  not  satisfied  with  Darwin's  own  state- 
ments on  this  subject  should  examine  :\Iiill(M''s  Fcrtili-atinn 
of  Elowers  (translated  by  D'Arcy  W.  Thonii)son),  in  whirh 
details  are  given  of  the  fertilisation  of  abuut  100  species  of 
alpine  plants  by  insects,  while  a  General  "Retrospect  gives  a 
most  valuable  summary  of  the  conclusions  and  teadiings  on 
the  whole  subject.  As  regards  the  general  question  of  the  u^^ 
and  purposes  of  colour  in  nature  the  late  Grant  Allen's  inter- 
esting and  philosophical  work  on  The  Colour  Sense  >hnuld  bo 
studied.  Any  one  who  does  so  will  be  satisfied  of  the  general 
truth  of  Darwin's  doctrines  though  there  are  a  few  errors  in 
the  details.  As  an  example  of  the  fascinatinjr  stvle  of  the 
book  I  will  quote  the  following  paragraph  comparing  insect- 
agency  with  that  of  man  in  modifving  and  beautit'vinfr  the 
face  of  nature.  After  describing  the  great  alterations  man 
has  made,  and  the  large  areas  he  has  modified  for  his  own 
purposes,  the  author  thus  proceeds : 

"But  all  these  alterations  are  mere  surface  scratches  coniparod 
with  the  immense  revolution  wrought  in  the  features  of  nature  l\v 
the  unobtrusive  insect.  Half  the  flora  of  tlie  earth  has  taken  the 
imprint  of  his  likes  and  his  necessities.  While  man  has  only  tilK'd 
a  few  level  plains,  a  few  great  river-valleys,  a  few  peninsular  moun- 
tain slopes,  leaving  the  vast  mass  of  earth  unloudied  hy  liis  hand, 
the  insect  has  spread  himself  over  every  land  in  a  thousand  sliapes, 
and  has  made  the  whole  flowering  creation  sul)servient  to  liis  daily 
wants.  His  buttercup,  his  dandelion,  and  his  meadow-sweet  grow- 
thick  in  every  English  field.  TTis  thyme  elothes  the  hill-side:  his 
heather  purples  the  bleak  grey  moorland.  HiLrh  up  among  the 
Alpine  heights  his  gentian  spreads  itsi'lf  in  lakes  of  blue:  amid 
the  snows  of  the  Himalayas  his  rhododendrons  gleam  with  crimson 
light.     The  insect  has  thus  turned  the  whole  surface  of  the  eartli 


334  THE  WORLD  OF  LIFE 

into  a  boundless  flower-garden,  which  supplies  him  from  year  to 
year  with  pollen  or  honey,  and  itself  in  turn  gains  perpetuation  by 
the  baits  it  offers  for  his  allurement." 

Although  I  wholly  agree  with  my  lamented  friend  in  attrib- 
uting the  origin  and  development  of  flowers  to  the  visits  of 
insects,  and  the  consequent  advantage  of  rendering  many  spe- 
cies of  flowers  conspicuous  and  unlike  others  flowering  at  the 
same  time,  thus  avoiding  the  waste  and  injury  of  the  frequent 
crossing  of  distinct  species,  yet  I  do  not  consider  that  the 
whole  of  the  phenomena  of  colour  in  nature  is  thereby  ex- 
plained. 

In  my  book  on  Tropical  E'ature  I  devoted  two  chapters  to 
the  Colours  of  Animals  and  Plants,  and  I  opened  the  discussion 
with  the  following  remarks,  which  indicate  my  present  views 
on  the  subject.     I  will,  therefore,  give  a  few  passages  here: 

"  There  is  probably  no  one  quality  of  natural  objects  from  which 
we  derive  so  much  pure  intellectual  enjoyment  as  from  their  col- 
ours. The  heavenly  blue  of  the  firmament,  the  glowing  tints  of 
sunset,  the  exquisite  purity  of  the  snowy  mountains,  and  the  end- 
less shades  of  green  presented  by  the  verdure-clad  surface  of  the 
earth,  are  a  never-failing  source  of  pleasure  to  all  who  enjoy  the 
inestimable  gift  of  sight.  Yet  these  constitute,  as  it  were,  but  the 
frame  and  background  of  a  marvellous  and  ever-changing  picture. 
In  contrast  with  these  broad  and  soothing  tints,  we  have  presented 
to  us,  in  the  vegetable  and  animal  worlds,  an  infinite  variety  of 
objects  adorned  with  the  most  beautiful  and  the  most  varied  hues. 
Flowers,  insects,  and  birds  are  the  organisms  most  generally  orna- 
mented in  this  way;  and  their  symmetry  of  form,  their  variety  of 
structure,  and  the  lavish  abundance  with  which  they  clothe  and 
enliven  the  earth,  cause  them  to  be  objects  of  universal  admiration. 
The  relation  of  this  wealth  of  colour  to  our  mental  and  moral  na- 
ture is  indisputable.  The  child  and  the  savage  alike  admire  the 
gay  tints  of  flower,  bird,  and  insect;  while  to  many  of  us  their 
contemplation  brings  a  solace  and  enjoyment  which  is  wholly  ben- 
eficial. It  can  then  hardly  excite  surprise  that  this  relation  was 
long  thought  to  afford  a  sufficient  explanation  of  the  phenomena 


GENERAL  AD.U^TATIOXS  335 

of  colour  in  nature,  and  this  received  great  support  from  the  dilTi- 
culty  of  conceiving  any  other  use  or  meaning  in  the  colours  with 
which  so  many  natural  objects  are  adorned.  Why  should  the 
homely  gorse  be  clothed  in  golden  ruiiiiuiit,  and  the  prickly  cactus 
be  adorned  with  crimson  bells?  Why  sliould  our  fields  be  gay  with 
buttercups,  and  the  heather-clad  mountains  be  clad  in  purple  robes? 
Why  should  every  land  produce  its  own  peculiar  floral  gems,  and 
the  alpine  rocks  glow  with  beauty,  if  not  for  the  contemplation  and 
enjoyment  of  man?  What  could  be  the  use  to  the  butterfly  of 
its  gaily-painted  wings,  or  to  the  humming-bird  of  its  jewelled 
breast,  except  to  add  the  final  touches  to  a  world-picture  calculated 
at  once  to  please  and  to  refine  mankind?  And  even  now,  with  all 
our  recently  acquired  knowledge  of  this  subject,  who  shall  say 
that  these  old-world  views  were  not  intrinsically  and  fundamentally 
sound;  and  that  although  we  now  know  that  colour  has  *  uses ' 
in  nature  that  we  little  dreamt  of,  yet  the  relations  of  those  colours 
—  or  rather  of  the  various  rays  of  light  —  to  our  senses  and  emo- 
tions may  not  be  another,  and  more  important  use  which  they  sub- 
serve in  the  great  system  of  the  universe  ?  " 

The  above  passage  was  written  more  than  forty  years  ago, 
and  I  now  feel  more  deeply  than  ever  that  the  concluding 
paragraph  expresses  a  great  and  fundamental  truth.  Although 
in  the  paragraph  succeeding  that  which  I  have  quoted  from 
Grant  Allen's  book,  he  refers  to  my  view  (stated  above)  as 
being  ''  a  strangely  gratuitous  hypothesis,"  I  now  propose  to 
give  a  few  additional  reasons  for  thinking  it  to  be  subr^tantially 
correct. 

The  first  thing  to  be  noticed  is,  that  the  insects  whose  per- 
ceptions have  led  to  the  production  of  variously  coloured  flowers 
are  so  very  widely  removed  from  all  the  higher  animals  (birds 
and  mammals)  in  their  entire  organisation  that  we  have  no 
right  to  assume  in  them  an  identity,  or  even  a  similarity,  of 
sensation  with  ourselves.  That  they  see  is  certain,  but  that 
their  sensation  of  sight  is  the  sanio  ns  our  own.  or  even  at  all 
closely  resembling  it,  is  highly  improbable  Still  niorc  improb- 
able is  it  that  their  perception  of  oolour  i<  the  same  as  ours, 
their  organ  of  sight  and  their  whole  nervous  system  being  so 


336  THE  WORLD  OF  LIFE 

very  different,  and  the  exact  nature  of  their  senses  being  un- 
known. Even  a  considerable  percentage  of  men  and  women 
are  more  or  less  colour-blind,  yet  some  diversity  of  colour  is 
perceived  in  most  cases.  The  purpose  of  colour  in  relation 
to  insects  is  that  they  should  distinguish  between  the  colours 
of  flowers  which  are  otherw^ise  alike  and  which  have  no  per- 
fume. It  is  not  at  all  necessary  that  the  colours  we  term  blue, 
purple,  red,  yellow,  etc.,  should  be  seen  as  we  see  them,  or 
even  that  the  sight  of  them  should  give  them  pleasure. 

Again,  the  use  of  colour  to  us  is  by  no  means  of  the  same 
nature  as  it  is  to  insects.  It  gives  us,  no  doubt,  a  greater 
facility  of  differentiating  certain  objects,  but  that  could  have 
been  obtained  in  many  other  ways  —  by  texture  of  surface, 
by  light  and  shade,  by  diversity  of  form,  etc.,  and  in  some 
cases  by  greater  acuteness  of  smell ;  and  there  are  very  few 
uses  of  colour  to  us  which  seem  to  be  of  "  survival  value  ''- — 
that  is,  in  which  a  greater  or  less  acuteness  of  the  perception 
would  make  any  vital  difference  to  us  or  would  lengthen  our 
lives.  But  if  so,  the  exquisite  perception  of  colour  we  nor- 
mally possess  could  not  have  been  developed  in  our  ancestors 
through  natural  selection ;  while  what  we  call  the  '^  aesthetic 
sense,''  the  sense  of  beauty,  of  harmony,  of  indescribable  charm, 
which  nature's  forms  and  colouring  so  often  gives  us  is  still 
further  removed  from  material  uses.  Another  consideration 
is,  that  our  ancestors,  the  Mammalia,  derived  whatever  colour- 
sense  they  possess  almost  wholly  from  the  attractive  colours 
of  ripe  fruits,  hardly  at  all  from  the  far  more  brilliant  and 
varied  colours  of  flowers,  insects,  and  birds.  But  the  colours 
of  wild  fruits,  which  have  been  almost  entirely  developed  for 
the  purpose  of  attracting  birds  to  devour  them  and  thus  to 
disperse  their  seeds,  are  usually  neither  very  brilliant  nor 
very  varied,  and  are  by  no  means  constant  indications  to  us 
of  what  is  edible.  It  might  have  been  anticipated,  therefore, 
that  our  perception  of  colour  would  have  been  inferior  to  that 
of  birds  and  mammals  generally,  not,  as  is  almost  certainly 
the  case,  very  much  superior,  and  so  bound  up  Avith  some  of 


GENERAL  ADAPTATIONS 


.»  .1  T 


our  higher  intellectual  achievements,  tiial  \Uv  total  absence 
of  perception  of  colour  would  have  checked,  or  pi  rliaps  wholly 
prevented,  all  those  recent  discoveries  in  spcctrosc^opy  which 
now  form  so  powerful  a  means  of  acquiring  an  extended  knowl- 
edge of  the  almost  illimitable  universe. 

I  venture  to  think,  therefore,  that  we  Jiave  good  reason  to 
believe  that  our  colour-perceptions  have  not  been  developed  in 
us  solely  by  their  survival-value  in  the  struggle  for  existenee ; 
which  is  all  ^ve  could  have  acquired  if  the  views  of  such  think- 
ers as  Grant  Allen  and  Professor  Ilaeckel  represent  the  wln.b* 
truth  on  this  subject.  They  seem,  on  the  other  hand,  to  have 
been  given  us  with  our  higher  aesthetic  and  moral  attributes, 
as  a  part  of  the  needful  equipment  of  a  being  whose  spiritual 
nature  is  being  developed,  not  merely  to  satisfy  material  needs, 
but  to  fit  him  for  a  higher  and  more  enduring  life  of  continued 
progress. 

Colours  of  Fruits:  a  Suggestion  as  to  Nuts 

As  flow^ers  have  been  developed  through  insects,  so  have 
edible  fruits  been  developed  and  coloured  so  that  birds  may 
assist  in  the  dispersal  of  their  seeds ;  while  inedible  fruits  have 
acquired  endlessly  varied  hooks  or  sticky  exudations  in  ord<'r 
that  they  may  attach  themselves  to  the  fur  of  quadrupeds  or  the 
feathers  of  birds,  and  thus  obtain  extensive  dissemination.  All 
this  was  clearly  seen  and  briefly  stated  by  Darwin,  and  has 
been  somewdiat  fully  developed  by  myself  in  the  work  already 
quoted:  but  there  is  one  point  on  which  I  wish  to  mai:i*  an 
additional  suggestion. 

In  my  Tropical  Nature  I  referred  to  Grant  Allen's  view 
(in  his  Physiological  Esthetics)  that  nuts  were  ''  not  intended 
to  be  eaten";  and  in  my  Darwinism  (p.  305)  I  adopted  this 
as  being  almost  self-evident,  because,  though  very  largely  edible, 
they  are  always  protectively  coloured,  being  green  when  unrijKi 
and  brow^n  when  they  fall  u])ou  the  ground  among  the  decay- 
ino"  folia2:e.  ^foreover,  thoir  outer-coverings  arc  often  prickly, 
as  in  the  sweet-chestnut,  or  bitter  as  in  the  walnut,  while  their 


338  THE  WORLD  OF  LIFE 

seed-boxes  are  often  very  hard,  as  in  the  hazel-nut,  or  intensely 
so_,  as  in  the  Brazil-nut  and  many  other  tropical  species. 

But,  on  further  consideration,  1  believe  that  this  apparently 
obvious  conclusion  is  not  correct;  and  that  nuts  are,  as  a  rule, 
intended  to  be  eaten.  I  am  not  aware  that  this  question  has 
yet  been  discussed  by  botanists,  and  as  it  is  one  of  much  inter- 
est and  exhibits  one  of  the  curious  and  indirect  ways  in  which 
nature  works  for  the  preservation  of  species,  both  in  the  vege- 
table and  animal  world,  I  will  briefly  explain  my  views. 

The  first  point  for  our  consideration  is,  that  most  nuts  are 
edible  to  some  animals,  and  a  large  number  are  favourite  foods 
even  to  ourselves.  Then  they  are  all  produced  on  large  trees 
or  shrubs  of  considerable  longevity,  and  the  fruits  (nuts, 
acorns,  etc.)  are  produced  in  enormous  quantities.  If  now 
we  consider  that  in  all  countries  which  are  undisturbed  by 
man,  the  balance  between  forest  and  open  country,  and  be- 
tween one  species  and  another,  only  changes  very  slowly  as 
the  country  becomes  modified  by  geographical  or  cosmical 
causes,  we  recognise  that,  as  in  the  case  of  animals,  the  number 
of  individuals  of  each  species  is  approximately  constant,  and 
there  is,  broadly  speaking,  no  room  for  another  plant  of  any 
particular  kind  till  a  parent  plant  dies  or  is  destroyed  by  fire 
or  tempest.  Imagine  then  the  superfluity  of  production  of 
seed  in  an  oak,  a  beech,  or  a  chestnut  forest;  or  in  the  nut- 
groves  that  form  their  undergrowth  in  favourable  situations. 
Countless  millions  of  seeds  are  produced  annually,  and  it  is 
only  at  long  intervals  of  time,  when  any  of  the  various  causes 
above  referred  to  have  left  a  space  unoccupied,  that  a  few 
seeds  germinate,  and  the  best  fitted  survives  to  grow  into  a 
tree  which  may  replace  its  predecessor. 

But  when  every  year  ten  thousand  millions  of  seeds  fall 
and  cannot  produce  a  tree  that  comes  to  maturity,  any  cause 
which  favoured  their  wider  dispersal  would  be  advantageous, 
even  though  accompanied  by  very  great  destruction  of  seeds, 
and  such  a  cause  is  found  when  they  serve  as  food  to  herbiv- 
orous mammals.     For  most  of  these  go  in  herds,  such  as  swine, 


GENERAL  AUAriATlOXS  339 

peccaries,  deer,  cattle,  horses,  etc.,  and  wlieu  .such  animals  are 
startled  while  feeding  and  scamper  away,  two  results,  useful 
to  the  species  whose  fruit  they  are  feedin-,^  upon,  follow.  As 
the  acorns,  chestnuts,  etc.,  usually  lie  thickly  un  the  ground, 
some  will  be  driven  or  kicked  along  wiih  the  herd;  an<l  this 
being  repeated  many  times  during  a  season  and  year  after 
year,  a  number  of  seeds  are  scattered  Ixyond  the  limits  of  the 
j^arent  trees.  By  this  process  seeds  will  often  reach  places 
they  would  not  attain  by  ordinary  means,  and  may  thus  be 
effective  in  extending  the  range  of  the  species.  It  would  also 
often  happen  that  seeds  would  be  trodden  into  soft  or  wet 
ground  and  thus  be  actually  planted  by  the  devouring  animals; 
and  being  in  this  case  placed  out  of  sight  till  the  herds  had 
left  the  district  would  have  a  better  chance  of  cominjr  to 
maturity. 

XoAv  one  such  success  in  a  year  would  more  than  compensate 
to  the  species  for  millions  of  seeds  devoured,  and  it  would 
therefore  be  beneficial  to  a  species  to  produce  nuts  or  seeds  of 
large  size  and  in  great  quantities  in  order  to  attract  numbers 
of  mammals  to  feed  on  them.  This  is  quite  in  accordance 
with  nature's  methods  in  other  cases,  as  Darwin  has  shown  in 
the  case  of  pollen.  The  very  curious  fact  of  the  I5razil-nut 
having  such  a  very  hard  shell  to  the  triangular  seeds  and  a  still 
harder  covering  to  the  globular  fruit,  which  falls  from  the  very 
lofty  trees  without  opening,  and  has  to  bo  broken  open  with 
an  axe  by  the  seed-collectors,  is  another  example.  This  is  saiil 
not  to  open  naturally  to  let  the  seed  escape  for  a  year  or  more ; 
and  this  fact,  with  its  almost  perfect  globular  form,  would 
facilitate  its  being  scattered  to  a  considerable  distance  by  the 
feet  of  tapirs,  deer,  or  peccaries,  and  when  at  last  the  seeds 
fell  out,  perhaps  aided  by  the  teeth  or  feet  of  these  animals, 
some  of  them  would  almost  certainly  be  trodden  into  the 
ground,  and  this  would  be  facilitated  by  their  sidvangidar 
shape.  If  this  is  the  mode  of  dispersal  it  has  ]u*oved  very  suc- 
cessful, for  the  species  is  widely  srattorrd  iti  moderate-sized 
groves  over  a  considerable  portion  of  th(^   Amazonian   forests. 


340  THE  WOKLD  OF  LIFE 

The  main  facts  and  probabilities  clearly  point  to  the  conclu- 
sion that  the  extensive  group  of  nut-like  fruits  or  seeds  are 
intended  to  be  eaten,  not  by  birds  while  on  the  trees,  but  by 
ground -feeding  animals  —  to  be  devoured  wholesale,  in  order 
to  disperse  and  save  a  few  which  may  germinate  and  produce 
another  generation  of  trees. 

The  Colours  of  Plants  and  Animals  in  relation  to  Man 

The  views  of  Ilaeckel  and  of  the  whole  school  of  Monists, 
as  ^\^e\\  as  of  most  of  the  followers  of  Spencer  and  Darwin, 
are  strongly  antagonistic  to  the  idea  that  in  the  various  groups 
of  phenomena  w^e  have  so  far  touched  upon  there  has  been  in 
any  real  sense  a  preparation  of  the  earth  for  man;  and  those 
who  advocate  such  a  theory  are  usually  treated  with  scorn  as 
being  unscientiiic,  or  Avith  contempt  as  being  priest-ridden. 
Darwin  himself  was  quite  distressed  at  my  rejection  of  his 
own  conclusion  —  that  even  man's  highest  qualities  and  pow- 
ers had  been  developed  out  of  those  of  the  lower  animals  by 
natural  or  sexual  selection.  Several  critics  accused  me  of 
^'  appealing  to  first  causes  "  in  order  to  get  over  difficulties ; 
of  maintainins:  that  '^  our  brains  are  made  bv  God  and  our 
lungs  by  natural  selection  " ;  and  that,  in  point  of  fact,  "  man 
is  God's  domestic  animal."  This  was  when  I  published  my 
Contributions  to  the  Theory  of  Xatural  Selection,  in  IS 70,  its 
last  chapter  on  The  Limits  of  ^Natural  Selection  as  applied  to 
Man,  being  the  special  object  of  animadversion,  because  I 
pointed  out  that  some  of  man's  physical  characters  and  many 
of  his  mental  and  moral  faculties  could  not  have  been  pro- 
duced and  developed  to  their  actual  perfection  by  the  law  of 
natural  selection  alone,  because  they  are  not  of  survival  value 
in  the  struggle  for  existence. 

In  the  present  work  I  recur  to  the  subject  after  forty  years 
of  further  reflection,  and  I  now  uphold  the  doctrine  that  not 
man  alone,  but  the  whole  World  of  Life,  in  almost  all  its  varied 
manifestations,  leads  us  to  the  same  conclusion  —  that  to  afford 
any  rational  explanation  of  its  phenomena,  w^e  require  to  pos- 


GENERAL  ADAPT  AT  lOXS  341 

tulate  the  continuous  action  and  guidance  of  higher  intelli- 
gences; and  further,  that  these  have  prul)ahly  been  working 
towards  a  single  end,  the  development  of  intellectual,  moral, 
and  spiritual  beings.  I  will  now  indicate  briefly  how  the  facts 
adduced  in  the  present  and  preceding  chapters  tend  to  support 
this  view. 

Having  shown  in  the  last  chapter  that  the  phenomena  of 
groiuth  in  the  animal  world,  and  especially  as  manifested  in 
the  feathers  of  birds  and  the  transformation>  of  the  higlier 
insects,  are  absolutely  unintelligible  and  unthinkable  in  the 
absence  of  such  intelligence,  we  must  go  a  stc})  further  and 
assume,  as  in  the  highest  degree  proliable,  a  pur|)o>c  which 
this  ever-present,  directing,  and  organising  intelligence  has  had 
always  in  view.  We  cannot  help  seeing  that  we  ourselves  are 
the  highest  outcome  of  the  developmental  process  on  the  earth ; 
that  at  the  time  of  our  first  ajopearance,  plants  and  animals 
in  many  diverging  lines  had  approached  their  highest  develop- 
ment; that  all  or  almost  all  of  these  have  furnished  species 
"which  seem  peculiarly  adapted  to  our  purposes,  whether  as 
food,  as  providing  materials  for  our  clothing  and  our  varied 
arts,  as  our  humble  servants  and  friends,  or  as  gratifying  our 
highest  faculties  by  their  beauty  of  form  and  colour :  and  as 
our  occupation  of  the  earth  has  already  led  to  the  extinction 
of  many  species,  and  seems  likely  ultimately  to  destroy  many 
more  except  so  far  as  we  make  special  efforts  to  preserve  them, 
we  must,  I  think,  assume  that  all  these  consequences  of  our 
development  were  foreseen,  and  that  results  which  srrm  to  bo 
so  carefully  adapted  to  our  wants  during  our  growing  civilisa- 
tion were  really  prepared  for  us.  If  this  be  so,  it  follows  that 
the  much-despised  anthropomorphic  view  of  the  whole  develop- 
ment of  the  earth  and  of  organic  nature  was,  after  all,  tho 
true  one. 

But  if  the  view  now  advocated  is  not  so  wholly  unscientific, 
so  utterly  contemptible  as  it  has  hitherto  been  declared  to  bo 
by  many  of  our  great  nuthnrities,  it  is  certainly  advisable  to 
show  how  various  facts  in   nature  bear  upon   it   and   are  ex- 


342  .THE  WOKLD  OF  LIFE 

plained  by  it.     I  will  therefore  now  add  a  few  more  consid- 
erations to  those   I  have  hitherto  set  forth. 

On  the  question  of  the  colour-sense  I  have  already  argued 
that  though  it  may  exist  in  birds  and  insects,  it  is  hardly  likely 
that  it  produces  any  such  high  aesthetic  pleasure  as  it  does  in 
our  own  case.  All  that  the  evidence  shows  is,  that  thev  do 
perceive  what  are  to  us  broad  differences  of  colour,  but  we  have 
no  means  whatever  of  knowing  n:]iai  they  really  perceive.  It 
is  a  suggestive  fact  that  colour-blind  persons,  though  they  do 
not  see  red  and  green  as  strongly  contrasted  as  do  those  with 
normal  vision,  yet  do  perceive  a  difference  between  them.  It 
is  therefore  quite  possible  that  birds  may  see  differences  be- 
tween one  strongly  marked  colour  and  another  without  any 
sense  of  what  we  should  term  colour,  and  at  all  events  without 
seeing  ''  colours  "  exactly  as  we  see  them.  It  is  now  generally 
admitted  that  birds  arose  out  of  primitive  reptiles,  and  from 
their  very  origin  have  been  quite  distinct  from  mammals, 
which  latter  probably  diverged  a  little  later  from  a  different 
stock  and  in  a  somewhat  different  direction.  The  eyes  of  both 
were  developed  from  the  already  existing  reptilian  eye,  and 
their  type  of  binocular  vision  may  be  very  similar.  But  at 
that  early  period  there  were,  it  is  believed,  no  coloured  flowers 
or  edible  coloured  fruits,  and  it  is  probable  that  the  perception 
of  colour  arose  at  a  much  later  period.  It  is  therefore  unlikely 
that  a  faculty  separately  developed  in  two  such  fundamentally 
different  groups  of  organisms  should  be  identical  in  degree  or 
even  in  nature  unless  its  use  and  purpose  were  identical.  But 
birds  are  much  more  extensive  fruit-eaters  than  are  mammals, 
the  latter,  as  we  have  seen,  being  feeders  on  nuts  which  are 
protectively  tinted  rather  than  on  fruits,  while  their  largely 
developed  sense  of  smell  would  render  very  accurate  perception 
of  colour  needless.  It  is  suggestive  that  the  orang-utan  of 
Borneo  feeds  on  the  large,  green  spiny  Darian  fruit ;  and  I 
have  also  seen  them  feeding  on  a  green  fruit  which  was  re- 
pulsively bitter  to  myself.  Our  nearest  relatives  among  exist- 
ing quadrupeds   do   not   therefore   seem  to   have   any  need   of 


GExXEEAL  ADAPTATiUAS  343 

a  refined  colour-sense.  AVliy  then  should  ii  have  been  so  highly 
developed  in  us?  It  was  one  of  the  finKhmir^ntnl  maxims  of 
Darwin  that  natural  selection  couhl  not  prudiK-u  absolute,  but 
only  relative  perfection;  and  airain,  that  no  species  could 
acquire  any  faculty  beyond  its  needs. 

The  same  ar^iments  will  apply  even  more  strongly  in  the 
case  of  insects.  They  appear  to  recognise  the  colour-,  the 
formSj  and  the  scents  of  flowers,  but  we  can  only  vagufly  guess 
at  the  nature  and  quality  of  their  actual  sensations.  Their 
whole  line  of  descent  is  so  very  far  removed  from  that  of  the 
birds  that  it  is  in  the  highest  degree  iinpnjbable  that  there  is 
any  identity  even  in  their  lower  mental  faculties  with  those 
of  birds.  For  the  colour-sense  is  mental,  not  })hysical ;  it 
depends  partly  on  the  organ  of  vision,  but  more  fundamentally 
on  the  nature  of  the  nervous  tissues  which  transform  the  etlects 
of  light-vibrations  into  the  visual  impressions  which  irc  rec- 
ognise as  colour,  and  ultimately  on  some  purely  mental  faculty. 
But  the  colour-sense  in  insects  may  be  quite  other  than  the 
bird's  or  than  our  own,  and  mav  in  most  cases  be  combined 
with  scent,  and  often  with  form  to  produce  the  recognition 
of  certain  objects,  which  is  all  they  require. 

Yet  insects,  birds,  and  the  flowers  and  fruits  which  attract 
them,  all  exhibit  to  our  vision  nearlv  the  same  ranjje  of  the 
colour-scheme,  and  a  verv  similar  intensitv,  brilliancv,  and 
purity  of  colour  in  particular  cases;  which  is  highly  remark- 
able if  their  respective  needs  were  the  only  etiicient  causes  in 
the  production  of  these  colours.  Looking  first  at  flow(  rs,  how 
very  common  and  conspicuous  are  those  of  a  yelh»w  colour, 
yet  far  beyond  the  average  are  the  rich  orange  petals  of  tlie 
Escholtzia  and  the  glistening  splendour  of  st^me  of  our  butter- 
cups; red  and  purples  are  innumerable,  yet  in  the  Lobelia 
fulqens  and  some  other  flowers  we  r(\'ieh  an  intensity  of  huo 
which  seem  to  us  un^urpassahly  b(\iutiful;  blues  of  the  type 
of  the  campanulas  or  the  v.'irious  blue  lillaceir  are  all  in  tlieir 
way  charming,  but  in  the  blue  salvia  (Salvia  patens)  the 
spring  gentian  {Geniiana  vcrna),  and  a  few  others,  we  perceive 


U4:  THE  WOJRLD  OF  LIFE 

a  depth  and  a  purity  of  liue  which  seem  to  have  reached  the 
limits  of  the  possible.  We  may  surely  ask  ourselves  whether 
these  exquisite  refinements  of  mere  colour  as  well  as  the  in- 
finity of  graceful  forms,  and  the  indescribable  delicacies  of 
texture  and  of  grouping,  are  all  strictly  utilitarian  in  regard 
to  insect-visitors  and  to  ourselves.  To  them  the  one  thing 
needful  seems  to  be  a  sufficient  amount  of  difference  of  any 
kind  to  enable  them  to  distinguish  among  species  which  grow 
in  the  same  localitv  and  flower  at  the  same  time. 

Special  Cases  of  Bird-colouration 

Coming  now  to  birds,  we  find  the  colours  with  which  they 
are  decorated  to  be  fully  equal  in  variety  and  purity  of  tint 
to  those  of  flowers,  but  extending  still  further  in  modifications 
of  texture,  and  in  occasionally  rivalling  minerals  or  gems  in 
the  brilliancy  of  their  metallic  lustre.  The  exquisite  blues 
and  vinous  purples,  reds  and  yellows  of  the  chatterers  and 
manakins,  the  glorious  metallic  sheen  of  the  trogons,  of  many 
of  the  humming-birds,  and  of  the  long-tailed  paradise-bird ; 
the  glistening  cinnabar-red  of  the  king-bird  of  paradise,  ap- 
pearing as  if  formed  of  spun-glass ;  the  silky  orange  of  the 
cock-of-the-rock  and  the  exquisite  green  of  the  Malayan  crested 
gaper,  are  only  a  few^  out  of  thousands  of  the  extreme  refine- 
ments of  colour  with  which  birds  are  adorned. 

Add  to  these  the  marvellous  ornaments  with  which  the  males 
are  so  frequently  decorated,  the  crests  varying  from  the  feath- 
ery dome  of  the  umbrella  bird,  to  the  large  richly  coloured 
crest  of  the  roval  flvcatcher  of  Brazil,  and  the  marvellous  blue 
plumes  from  the  head  of  the  fern-bearing  bird  of  paradise 
(Pteridopliora  Alherti),  with  a  thousand  others  hardly  in- 
ferior, and  we  shall  more  than  ever  feel  the  want  of  some 
general  and  fundamental  cause  of  so  much  beauty. 

All  this  w'ealth  of  colour,  delicacy  of  texture  and  exuber- 
ance  of  ornament,  has  been  explained  hitherto  as  being  utili- 
tarian in  two  ways  only:  (1)  that  they  are  recognition-marks 
of  use  to  each  species,  more  especially  during  its  differentiation 


GEXEKAL  ADAI^TATIONS  345 

as  a  species;  and  (2)  as  inllucncing  female  choice  of  the  must 
ornamental  males,  and  tlicrclure  of  use  to  each  species  in  the 
struggle  for  existence.  The  former  I  have,  I  tliink,  proved  to 
be  a  true  cause;  the  latter  I  reject  for  reasons  given  ii»  my 
Darwinism.  I  there  give  an  alternative  solution  of  the  prol>- 
lem  which  I  still  think  to  be  fundnmontally  correct  and  whicli 
has  been  arrived  at  by  Weismann  and  others  from  theoretical 
considerations  to  whicli    1    may  advert   hiter  on. 

C olouration  of  Insects 

Passing  now  to  tlie  order  of  insects  wliich  perhaps  pxhil»its 
the  greatest  range  of  colour-display  in  the  wh(de  of  the  organic 
world  —  especially  in  the  order  Lepido])tera,  we  find  the  dif- 
ficulties in  the  way  of  a  purely  utilitarian  solution  still  greater. 
Any  one  who  is  ac(iuainted  with  this  order  of  insects  in  its 
fullest  development  in  the  equatorial  zone  of  the  great  conti- 
nents, will  recognise  liow  impossible  it  is  to  give  any  ade<piato 
conception  of  its  wealth  of  colour-decoration  by  a  mere  verbal 
description,  "^'et  the  attempt  must  be  made  in  order  to  com- 
plete the  argument  1  am  founding  upon  a  consideration  of  the 
whole  of  the  facts  of  orc^anic  colouration. 

Even  in  the  temperate  zones  we  have  a  rich  display  of  colour 
and  marking  in  our  exquisite  little  blues,  our  silver-spotted 
fritillaries,  our  red-admiral,  our  peacock,  and  our  orange-tip 
butterflies,  and  on  the  Continent,  the  two  swallow-tails,  the 
apollo  butterflies,  the  fine  Chaaxcs  Jason,  and  many  other*. 
But  these  are  absolutely  as  nothing  compared  to  the  wealth 
of  colour  displayed  in  the  eastern  and  western  tropics,  where 
the  average  size  is  from  two  to  three  times  ours,  and  the  num- 
bers, both  in  species  and  individuals  at  least  ten  times  as  great. 
Not  only  is  there  every  tint  of  red,  yellow,  Mue  and  gretMi, 
on  ground-colours  of  black  or  white  an<l  various  slunles  of 
brown  or  buff,  but  we  find  the  most  vivid  metallic  hlues  or 
silky  yellows  covering  a  largi'  j)orti<»ii  of  tlie  wing-surface  or 
displayed  in  n  variety  of  patteni<  ihat  i-  almost  bewildering 
in  its  varietv  and  beauty. 


346  THE  WOELD  OE  LIFE 

As  a  few  examples,  the  Callitliea  sapphira  of  the  Amazon 
is  of  a  soft,  celestial  blue  that  the  finest  lobelia  or  gentian 
cannot  surpass.  The  grand  Oenithoptera  Amphrisius,  and  its 
allies  has  the  hind  wings  of  an  intense  yellow  with  a  silky 
lustre,  while  0.  Prianius  and  many  allied  species  are  richly 
adored  with  metallic  green,  deep  orange,  or  violet-blue. 
Papilio  Ulysses  of  Amboyna  equals  in  size  and  colour  the 
splendid  blue  morphos  of  South  America ;  while  these  latter 
not  only  present  us  with  every  shade  of  blue  on  insects  of 
the  largest  size,  but  in  Morpho  cypris,  and  several  allied 
species  exhibit  an  intensity  of  colour  and  of  metallic  sheen 
that  is  equal  to  the  highest  efforts  of  nature  in  this  direction 
on  the  caps  or  the  gorgets  of  humming-birds,  on  the  glittering 
shields  of  the  Epimachidse  of  ^N^ew  Guinea,  or  on  such  precious 
gems  as  the  emerald,  the  sapphire,  the  ruby,  or  the  opal. 

The  exquisite  combinations  of  brilliant  colour  and  endless 
variety  of  pattern  to  be  found  among  the  small  Lycsenidae 
and  Erycinidse  of  both  hemispheres  must  be  passed  over;  as 
well  as  the  somewhat  larger  Catagrammas  whose  diversified 
upper  and  under  sides  are  a  constant  delight;  while  the  vast 
groups  of  the  Heliconidse  and  Danaidse,  inedible  to  most  birds 
and  lizards,  are  often  rendered  conspicuous  by  bold  contrasts 
of  the  purest  white,  yellow,  or  red,  on  a  blue-black  ground. 

Some  Extremes  of  Insect-Coloration 

There  are  some  examples  of  tropical  butterflies  in  which 
nature  may  be  said  to  have  surpassed  herself,  and  to  have 
added  a  final  touch  to  all  the  beauty  of  colour  so  lavishly  dis- 
played elsewhere.  These  are  to  be  found  in  a  few  species 
only  in  both  hemispheres,  and  are  therefore  the  more  remark- 
able. The  largest  butterfly  to  exhibit  this  form  of  colour  is 
the  Ornithoptera  magellanus,  from  the  Philippines,  whose 
golden-yellow  wings,  when  viewed  obliquely  acquire  the  chang- 
ing hues  of  polished  opals,  quite  distinct  from  any  of  its 
numerous  allies  which  possess  the  same  colour  but  with  what 
may  be  termed  a  silky  gloss.     In  the  same  part  of  the  world 


GEXEEAL  ADAriATlOXS  347 

(the  Bismarck  Archipelago)  there  is  a  day-flyinn;  i,„,th 
(Burgena  chalyhcata),  one  of  the  A<:aristifhi',  wIkjso  wings 
change  from  Mack  to  blue  and  a  fiery  opalcsci-nt  red.  In 
tropical  America  there  is  a  group  (»f  hutterilies  of  tlic  g«-nii8 
Papilio,  which  are  very  abuii(hiiit  botli  in  species  and  in«livid- 
uals,  whose  velvet-black  wings  liav(^  a  few  bands  or  -jiois  uf 
blue  or  green  on  the  upper  pair,  while  the  lower  have  a  ban<l 
of  spots  near  the  posterior  margin  of  a  brilliant  cTimsnn. 
Among  perhaps  a  hundred  species  with  this  general  style  oi 
coloration,  there  are  a  few  (perhaps  a  dozen)  in  which  ihe 
red  of  the  hind  wings,  when  viewed  very  obli(iu('ly  fn^ni  be- 
hind, changes  into  opalescent  and  then  into  a  curious  bluish 
phosphorescence  of  intense  brilliancy. 

I  am  informed  by  Dr.  K.  Jordan  (of  the  Tring  Zoohtgical 
Museum)  that  in  these  insects  the  black  ground  of  the  wing 
changes  also  into  metallic  blue,  which  seems  to  spread  over 
the  red  and  to  aid  in  the  production  of  the  phosphorescent 
effect.  This  is  so  marked  that  ^Ir.  Bates  gave  to  one  of  the 
new  species  he  described,  the  name  of  Papilu)  phosplionis. 
One  of  the  small  Er^'cinidae  (Euseldsia  prcvclara)  found  in 
the  Upper  Amazon  valley,  is  of  a  yellow  butf  colour,  with  a 
wonderful  opalescent  reflection  which  is  said  to  be  tlic  most 
intense  and  brilliant  in  the  whole  order  of  Lepidoptera  iuid 
probably  the  most  brilliant  colour  known. 

All  metallic  reflections  in  the  animal  world  are  what  aro 
called  interference-colours,  and  are  prttduced  by  excessively 
fine  lines  or  rugosities  on  polishe<l  surfaces,  or  by  ('<iually 
thin  transparent  lamina^.  It  is  probable  that  in  the  remark- 
able changing  glows  now  described,  l)olh  these  eauses  may 
come  into  play,  producing,  wlion  viewed  at  eertain  auirles, 
an  intensity  of  hue  resembling  those  of  the  linest  opals,  or 
sometimes  imitating  the  most  brilliant  glow-worms  or  fire- 
flies bv  means  of  reflecteil  light.  It  se(Mn<  |»rol)able  that  tliCi^e 
rare  hues  mav  be  nt'  a  pi-oleetivc  nature,  siui-e  a  pur-ning  bird 
miiilit  be  start  le(l  hv  tli*'  sudden  fla-hinrr  out  of  -n  l)rilliant  a 
light  and  thus  allow   the   inject    to  escape:    lnu    that    dor'<   not 


348  THE  WOKLD  OF  LIFE 

render  it  more  probable  that  the  infinitely  complex  arrange- 
ments by  which  such  structures  are  produced  and  transmitted 
unfailingly  to  offspring,  should  have  been  brought  about  for 
this  purpose  alone,  when  thousands  of  other  species  arrive 
at  the  same  end  by  far  simpler  means. 

E"ow  if  there  was  a  difficulty  in  the  view  that  all  the  wealth 
of  colour  and  beauty  in  birds  has  been  developed  solely  on 
account  of  its  utility  to  themselves,  that  difficulty  becomes 
greatly  increased  in  the  case  of  these  insects.  The  described 
butterflies  alone  are  already  far  more  numerous  than  birds, 
and  there  are  certainly  more  to  be  discovered  of  the  former 
than  of  the  latter.  Bates  well  observed  that  the  expanded 
wings  of  butterflies  seemed  to  have  been  used  by  nature  to 
write  thereon  the  story  of  the  origin  of  species.  To  this  we 
may,  I  think,  add  that  she  has  also  used  them,  like  the  pages 
of  some  old  illuminated  missal,  to  exhibit  all  her  powers  in 
the  production,  on  a  miniature  scale,  of  the  utmost  possibili- 
ties of  colour-decoration,  of  colour-variety,  and  of  colour- 
beauty  ;  and  has  done  this  by  a  method  which  appears  to  us 
unnecessarily  complex  and  supremely  difficult,  in  order  per- 
haps to  lead  us  to  recognise  some  guiding  power,  some  supreme 
mind,  directing  and  organising  the  blind  forces  of  nature  in 
the  production  of  this  marvellous  development  of  life  and 
loveliness. 

It  must  always  be  remembered  that  what  is  produced  on 
the  flow^er,  the  insect,  or  the  bird,  is  not  colour,  but  a  surface 
so  constituted  in  its  chemical  nature  or  mechanical  texture 
as  to  reflect  light  of  certain  w^ave-lengths  while  absorbing  or 
neutralising  all  others.  Colour  is  the  effect  produced  on  our 
consciousness  by  light  of  these  special  wave-lengths.  To  claim 
that  the  lower  animals,  especially  the  mammals,  perceive  all 
the  shades  and  intensities,  the  contrasts  and  the  harmonies  of 
colours  as  we  perceive  them,  and  that  they  are  affected  as  we 
are  with  their  unequalled  beauty  is  a  wholly  unjustified 
hypothesis.  The  evidence  that  such  sensations  of  colour  exist 
in  their  case  is  wholly  wanting.     All  wc  really  know  is,  that 


GENERA!.  Al  )ArTA  TK  ).\S  :]|;) 

they  appear  to  percoivo  (lifTcrciicfs  wlicn-  wc  j..  re.  nc  cnlour, 
but  it  has  not  hoen  ))!•(. vcd  liow  far  tlii-  iMi-ccption  cxtfinU, 
since  in  the  most  intollii^^cnl  «»f  tlu'sc,  (|(i«:>  and  horses,  the 
sense  of  smell  is  so  highly  developed  as  for  many  purposes  to 
take  the  place  of  vision. 

It  is  a  very  suggestive  fact  that  tho  tlioory  of  tlie  develop- 
ment of  the  colour-sense  through  its  utility,  receives  least  s\ij>- 
port  from  those  animals  Avhich  are  nearest  to  us,  and  from 
which  we  have  been  corporeally  developed  —  the  niannnals; 
rather  more  support  from  those  which  have  had  a  \vi(hdy  dif- 
ferent origin  —  the  birds ;  and  apparently  most  from  tlioso 
farthest  removed  from  us  —  the  insects,  for  whom  it  has  been 
claimed  that  we  owe  them  all  the  floral  beauty  of  the  vege- 
table kingdom,  through  their  refined  perception  of  ditTerences 
of  form  and  colour.  This  seems  to  me  to  be  a  kind  of 
redudio  ad  dbsurdum,  and  to  constitute  a  disproof  of  that 
whole  argument  as  a  final  cause  of  the  colour-sense.  On  the 
other  hand,  it  gives  the  strongest  support  to  the  view  that  the 
refined  perception  and  enjo\inent  of  colour  ive  possess  has 
not,  and  could  not  have  been  developed  in  us  by  its  survival- 
value  in  our  early  struggle  for  existence,  but  that  these  faculties 
are,  as  Huxley  remarked  in  reirard  to  his  eniovment  of  scenerv 
and  of  music,  ^^  gratuitous  gifts,''  and  as  such  are  powerful 
arsninients  for  ^'  a  benevolent  Author  of  the  Universe/'  * 

iSee  Darwinism  (3rd  ed.  1901),  p.  478,  Appendix. 


CHAPTEE  XVI 

THE  VEGETABLE  KINGDOM   IN  ITS  SPECIAL  EELATION 

TO    MAN 

It  is  obvious  that,  as  animal  life  has  from  its  very  origin 
depended  upon  and  been  developed  in  relation  to  plant  life, 
the  entire  organisation  of  the  former  would,  by  the  continuous 
action  of  variation  and  survival  of  the  fittest,  become  so 
harmoniously  adapted  to  the  latter,  that  it  would  inevitably 
have  every  appearance  of  the  plant  having  been  formed  and 
preordained  for  the  express  purpose  of  sustaining  and  benefit- 
ing the  animal.  This  harmonious  co-adaptation  cannot  there- 
fore be  adduced  as,  of  itself,  being  any  proof  of  design,  but 
neither  is  it  any  proof  against  it.  So  with  man  himself,  so 
far  as  his  mere  animal  wants  are  concerned,  his  dependence 
on  plants,  either  directly  or  indirectly,  for  his  entire  sus- 
tenance by  food,  and  therefore  for  his  very  life,  affords  no 
grounds  for  supposing  that  either  of  the  two  kingdoms  came 
into  existence  in  order  to  render  the  earth  a  possible  dwelling- 
place  for  him.  But  as  regards  those  special  qualities  in  which 
he  rises  so  far  above  all  other  animals,  and  especially  those 
on  which  the  higher  races  found  their  claim  to  be  "  civilised," 
there  seem  to  be  ample  grounds  for  such  an  argument,  as  I 
hope  to  be  able  to  show. 

Taking  first  the  innumerable  different  kinds  of  wood,  whose 
qualities  of  strength,  lightness,  ease  of  cutting  and  planing, 
smoothness  of  surface,  beauty,  and  durability,  are  so  exactly 
suited  to  the  needs  of  civilised  man  that  it  is  almost  doubtful 
if  he  could  have  reached  civilisation  without  them.  The  con- 
siderable range  in  their  hardness,  in  their  durabilitv  when  ex- 
posed  to  the  action  of  water  or  of  the  soil,  in  their  weight 
and  in  their  elasticity,   render  them  serviceable  to  him  in  a 

350 


PLANTS  IN  RELATIOX  TO  MAX  nr>i 

thousand  ways  which  arc  totally  removed  from  any  use  made 
of  them  by  the  lower  animals. 

Few  of  these  qualities  seem  essential  to  themsclvos  as  vege- 
table growths.  They  might  have  been  much  smaller,  which 
would  have  greatly  reduced  their  uses;  or  so  much  harder  as 
to  be  almost  unworkable;  or  so  liable  to  fracture  as  to  ho 
dangerous;  or  subject  to  rapid  decay  by  the  action  of  air,  or 
of  water,  or  of  sunshine,  so  as  to  be  suitable  for  temjuirarv 
purposes  only.  With  any  of  these  defects  they  miirht  have 
served  the  purposes  of  the  animal  world  (piite  as  well  as  they 
do  now;  and  their  actual  properties,  all  varyinir  alxuit  a  mean 
value,  which  serves  the  infinitely  varied  purposes  to  which  we 
daily  and  hourly  apply  them,  may  certainly  be  adducc<l  as  an 
indication  that  they  were  endowed  with  such  properties  in 
view  of  the  coming  race  wdiich  could  alone  utilise  them,  and 
to  whose  needs  they  minister  in  such  an  infinite  variety  of 
ways. 

As  one  example  of  what  such  a  different  quality  of  tind)er 
as  above  indicated  might  mean  let  us  remember  that  from  bo- 
fore  the  dawn  of  history  down  to  about  the  middle  of  the  last 
century  every  ship  in  the  world  was  built  of  wood.  lla<l  no 
wood  existed  suitable  for  sea-going  vessels,  the  whole  course  of 
history,  and  perhaps  of  civilisation,  would  have  been  dilTerent. 
Without  ships  the  Mediterranean  would  have  been  almost  as 
impassable  as  was  the  Atlantic.  America  would  be  still  un- 
known, as  well  as  Australia  and  possibly  S..iitli  Africa;  and 
the  whole  world  would  be  for  us  smaller  than  in  ilie  days  be- 
fore Columbus.  And  all  this  might  have  happened  had  tlie 
nature  of  vegetable  growth,  while  dift'ering  little  in  external 
form  and  equally  well  adapted  for  unintelligent  animal  life, 
not  possessed  those  special  qtuditics  which  fitted  it  for  minis- 
tering to  the  varied  needs  of  intellectual,  inventive,  and  ever 
advancing  man. 

But,  even  with  the  whole  vegetable  world  in  \\<  (Uitwanl 
aspect  and  mechanical  properties  exactly  as  it  is  now,  there 
are  still   a   thousand    wavs   in    which   it    ministers   to   tlie   needs 


352  THE  WOKLD  OF  LIFE 

of  our  ever-growing  civilisation,  whicli  have  little  or  no  re- 
lation to  the  animal  world  Avhich  grew  up  in  dependence  on 
it.  Leaving  out  of  consideration  the  vast  number  of  fruits, 
and  cereals,  and  vegetables  which  supply  him  with  varieties 
of  food,  which  may  be  of  more  importance  to  man  in  the 
future  than  thev  are  now,  let  us  take  first  the  innumerable 
drugs  which  enable  him  to  avoid  some  of  the  evils  brought 
upon  himself  by  his  ignorance,  his  dissipations,  or  his  wilful 
neglect.  The  pharmacopeias  of  every  country  and  every  age 
are  crowded  with  the  names  of  herbs  and  simples  used  with 
more  or  less  success  as  remedies  for  the  various  diseases  man 
was  supposed  to  be  heir  to,  and  if  many  of  these  were  alto- 
gether imaginary,  very  large  numbers  still  hold  their  place  as 
of  real  and  often  of  inestimable  value.  To  name  onlv  a  few 
of  the  best  known,  we  could  hardly  dispense  with  such 
common  drugs  as  aloes,  arnica,  belladonna,  calendula,  cascara, 
gentian,  jalap,  ipecacuanha,  nux  vomica,  opium,  podopholin, 
quinine,  rhubarb,  sarsaparilla,  and  a  host  of  others. 

To  these  we  mav  add  the  various  ''  balsams  "  so  much  used 
in  ancient  surgery  —  balm  of  Gilead,  friar's  balsam,  balsam 
of  Peru,  benzoin,  camphor,  etc. 

Then  there  are  the  ordinary  resins  and  gums  so  useful  in 
the  arts  —  copal,  dammar,  mastic,  kauri,  gum-arabic,  traga- 
canth,  asafoedita,  gamboge,  etc. 

Among  the  numerous  dyes  are  amatto.  Brazil-wood,  log- 
wood, camwood,  fustic,  indigo,  madder,  turmeric,  and  woad. 

Vegetable  oils,  used  for  cooking,  lighting,  perfumes, 
medicines,  etc.,  are  very  numerous.  Such  are  candle-nut, 
castor  oil,  coco-nut  oil,  colza  oil,  olive  oil,  cotton  seed, 
linseed,  and  rape-seed  oils,  cajeput  oil,  and  innumerable  others 
in  every  part  of  the  world,  known  or  yet  to  be  discovered. 

Perfumes  and  spices  are  also  extremely  abundant,  such  as 
caraways,  cinnamon,  cloves,  mace,  nutmegs,  patchouli,  pepper- 
mint, orris-root,  sandal  wood,  sassafras,  tonquinbeans,  vanilla, 
and  the  many  essential  oils  from  highly  perfumed  fruits  and 
flowers. 


PLAXTS   l.\    1  ii:  LAT  I  ().\    To   MAX  nnn 


•JJO 


Of  foods  and  drinks  not  used  l).v  ihc  lower  animals,  are 
arrowroot,  tapioca,  sa^^),  sugar,  wine,  l.cer,  i.-a,  eolTee,  :ind 
cocoa,  the  last  six,  wlicn  nscd  in  moderation,  Indn-,^  among 
the  choicest  gifts  of  nature. 

There  remain  a  number  of  vegetaMc  pn.diict-^  inv;duahle 
for  arts  and  manufaelures  —  cotton  and  tlax  for  (doihing, 
hemp  for  cordage,  rattan  and  bandjoo  for  tropical  furniture, 
boxwood  for  wood-engraving,  gutta-percha  for  machine  belts 
and  a  great  variety  of  economic  uses,  and  lastly  india-rubU.-r, 
one  of  the  greatest  essentials  of  our  chemieal  and  mechanical 
arts,  without  which  neither  the  electric  telegraph,  the  bicycle, 
nor  the  motor-car  could  have  reached  their  present  stage  of 
perfection,  while  no  doubt  many  equally  important  uses  re- 
main to  be  discovered. 

It  may  be  objected  that  so  many  of  these  varied  products 
have  been  shown  to  be  of  use  to  the  plants  themselves  as 
protections  against  injurious  insects  or  from  being  devoured 
in  their  young  state  by  herbivorous  mammals,  that  their  utility 
to  man  is  only  an  accidental  result,  and  of  no  real  signiticancc. 
But  this  objection  can  hardly  be  a  valid  one  when  we  consider 
the  enormous  number  of  beneficial  drugs,  highly  agreeable 
scents  and  spices,  useful  oils,  and  delicious  foods  or  drinks, 
that  are  among  the  commonest  of  vegetable  bye-products. 
There  seems  no  direct  connection  between  juices  or  volatile  oils 
which  are  distasteful  to  insects,  and  drugs  which  are  valuable 
medicines  in  the  case  of  human  diseases.  The  leaves  or  stems 
of  seedling  plants  needed  only  a  temporary  protection,  while 
the  juices  which  effect  it  not  only  increase  in  (piantity  dur- 
ing the  whole  life  of  the  plant,  but  are  transfornuil  into  such 
as  are  of  unmistakeable  value  to  civilised  man.  It  is  almost 
inconceivable  that  the  exquisite  fragrance  tleveloped  only  by 
roasting  the  seed  of  the  coifee  shnd)  should  be  a  chance  result 
of  the  nature  of  the  juices  essential  for  the  well-being  of  this 
particular  species;  or  that  the  strange  mechanical  properties 
of  india-rubber  should  be  developed  in  a  few  otdy  of  the  thou- 
sands of  species  having  a  ])rotective  milky  sap. 


35i  THE  WOELD  OF  LIFE 

Before  leaving  this  brancli  of  my  subject,  1  must  say  a  few 
words  on  the  indications  afforded  by  these  varied  products 
of  plant-life,  of  the  absolute  necessity  of  a  directive  power 
and  a  mind  of  the  highest  organising  intelligence  for  their 
production.  Quite  as  clearly,  perhaps  even  more  clearly  than 
for  the  development  of  the  bird's  feather  or  the  insect's  trans- 
formations, does  the  agency  of  such  a  supreme  mind  seem  to 
be  essential. 

Let  us  consider  first  the  extreme  simplicity  and  uniformity 
of  the  conditions  under  which  such  marvellously  diverse  re- 
sults are  produced.  A  very  large  proportion  of  the  vegetable 
products  useful  to  man  are  obtained  from  the  tropical  forests, 
where  the  temperature  is  more  uniform,  the  moisture  more 
constant,  and  the  trees  less  exposed  to  wind  than  anywhere 
else  in  the  world.  The  whole  organisation  of  the  higher 
plants  is,  as  compared  with  that  of  animals,  extremely  simple, 
and  they  are  wonderfully  similar  in  structure  to  each  other, 
even  in  distinct  genera  and  natural  orders.  The  roots,  the 
wood,  the  bark,  the  leaves,  are  substantially  of  the  same  type 
in  thousands  of  species.  All  alike  build  up  their  structures 
out  of  the  same  elements,  which  they  obtain  from  the  water 
and  the  few  substances  it  dissolves  out  of  the  soil,  from  the 
air  and  the  carbonic  acid  and  aqueous  vapour  it  contains. 
Yet  under  these  conditions  w^hat  a  seemingly  impossible 
variety  of  products  arise. 

When  the  modern  chemist  attempts  to  bring  about  the  same 
results  as  are  effected  by  nature  in  the  plant,  he  has  to  em- 
ploy all  the  resources  of  his  art.  He  has  to  apply  great  heat 
or  great  cold ;  he  uses  gas  or  electric  fires  and  crucibles ;  he 
requires  retorts  for  distillation,  and  air-tight  vessels  and  tubes 
for  the  action  of  his  reagents,  or  to  preserve  his  liquid  or 
gaseous  products ;  but  with  all  his  work,  carried  out  for  more 
than  a  century  by  thousands  of  earnest  students,  he  has  only 
been  able  to  reproduce  in  his  laboratory  a  limited  number  of 
organic  substances,  while  the  more   important  of  the  constit- 


PLAXTS   IX   IIEJ.ATIOX   To  MAX  35 


oo 


UGiits   of  liviug-  urgaiii.Niiis    i-cuiaiii    I'ar   Im'^uikI    his    pijwcrs   of 
yynthesis. 

The  conditions  under  wldcli  rial  hit  works  in  ilic  vpffotablc 
kingdom  are  the  very  (jpposite  of  all  this.  Starting  fr«>ni 
the  ripened  seed,  consisting  essentially  of  a  single  fertilised 
cell  and  a  surrounding  mass  of  nutritive  material,  a  root  is 
sent  out  into  the  soil  and  a  shoot  into  the  atmosphere,  from 
which  the  whole  plant  with  all  its  tissues  and  vessels  arc 
formed,  enabling  it  to  rise  up  into  the  air  so  as  to  obtain 
exposure  to  light,  to  lift  up  tons  weight  of  material  in  the 
form  of  limbs,  branches,  and  foliage  of  forest  trees,  often  to 
a  hundred  feet  or  more  above  the  surface,  by  means  of  forces 
whose  exact  mode  of  operation  is  still  a  mysten.^ ;  while  by 
means  of  the  very  same  tissues  and  vessels  those  recondite 
chemical  processes  are  being  carried  on  which  result  in  the 
infinitely  varied  products  already  very  brietly  referred  to. 

The  living  plant  not  only  builds  up  its  own  man-ellous 
structure  out  of  a  few  elements  supplied  to  it  either  in  a 
gaseous  or  liquid  state,  but  it  also  manufactures  all  the  aj> 
pliances  —  cells,  vessels,  fibres,  etc. —  needful  for  its  complex 
laboratory  work  in  producing  the  innumerable  l)V(v})roducts 
possessing  so  many  diverse  properties  useful  to  man,  but  which 
were  mostly  unneeded  by  the  remainder  of  the  animal  world. 

Usually  botanists  as  well  as  zoologists  are  satisfied  to  de- 
scribe the  minute  structure  of  the  organs  of  j)lants  or  animals, 
and  to  trace  out  as  far  as  possible  the  changes  that  occur  dur- 
ing growth,  without  any  reference  to  the  unknown  and  un- 
intelligible forces  at  work.  As  Weismann  has  state<l,  the 
fundamental  question — ''the  causes  and  mechanism  by  which 
it  comes  about  that  they  (the  germicides  or  physinlogical 
units)  are  always  in  the  right  place  and  develoj)  into  colls 
at  the  right  time" — is  rarely  or  never  touched  uptju.' 
Modern  theories  of  heredity  take  for  granted  the  essential 
phenomena  of  life  —  nutrition,  assiniilati(ui,  antl  growth. 

1  Tlie  Germ  riasiii,  p.  4. 


356  THE  WORLD  OY  LIFE 

I  find,  however,  that  Professor  Anton  Kemer,  in  his  great 
■work  on  The  Natural  History  of  Plants,  fully  recognises  this 
great  fundamental  problem,  and  even  recurs  to  the  much 
derided  "  vital  force ''  as  the  only  help  to  a  solution  of  it. 
He  says: 

"  The  phenomena  observed  in  living  protoplasm,  as  it  grows  and 
takes  definite  form,  cannot  in  their  entirety  be  explained  by  the 
assumption  of  a  specific  constitution  of  protoplasm  for  every  dis- 
tinct kind  of  plant,  though  this  hypothesis  may  prove  useful  when 
we  enquire  into  the  origin  of  new  species." 

Again  he  says: 

"  In  former  times  a  special  force  was  adduced,  the  force  of  life. 
More  recently,  when  many  phenomena  of  plant-life  had  been  suc- 
cessfully reduced  to  simple  chemical  and  mechanical  processes,  this 
vital  force  was  derided  and  effaced  from  the  list  of  natural 
agencies.  But  by  what  name  shall  we  now  designate  that  force  in 
nature  which  is  liable  to  perish  whilst  the  protoplasm  suffers  no 
physical  alteration  and  in  the  absence  of  any  extrinsic  cause;  and 
which  yet,  so  long  as  it  is  not  extinct,  causes  the  protoplasm  to  move, 
to  enclose  itself,  to  assimilate  certain  kinds  of  fresh  matter  coming 
within  the  sphere  of  its  activity  and  to  reject  others,  and  which 
when  in  full  action  makes  the  protoplasm  adapt  its  movements  un- 
der external  stimulation  to  existing  conditions  in  the  manner  which 
is  most  expedient? 

"  This  force  in  nature  is  not  electricity  nor  magnetism ;  it  is  not 
identical  with  any  other  natural  force;  for  it  manifests  a  series  of 
characteristic  effects  which  differ  from  all  other  forms  of  energ}\ 
Therefore,  I  do  not  hesitate  again  to  designate  as  '  vital  force '  this 
natural  agency,  not  to  be  identified  with  any  other,  whose  immedi- 
ate instrument  is  the  protoplasm,  and  whose  peculiar  effects  we  call 
life.  The  atoms  and  molecules  of  protoplasm  only  fulfil  the  func- 
tions which  constitute  life  so  long  as  they  are  swayed  by  this  vital 
force.  If  its  dominion  ceases  they  yield  to  the  operation  of  other 
forces.  The  recognition  of  a  special  natural  force  of  this  kind  is 
not  inconsistent  with  the  fact  that  living  bodies  may  at  the  same 
time  be  subject  to  other  natural  forces"  (p.  52). 


PLA^s'TS  l.\  KEL.VTiO.\    it)  .MAX  357 

And  again,  after  discussing  the  various  effects  pro<luce(l  by 
that  wonderful  substance  chlorophyll,  he  says: 

"  We  see  the  effective  apparatus,  we  niugnisu  the  f(x)(l-ga.scg 
and  food-salts  collected  for  working  up,  wo  know  that  tlie  nun's 
rays  act  as  the  motive  force,  and  we  also  identify  the  prodiu-t^ 
which  appear  completed  in  the  chloropliyil  granules.  By  careful 
comparison  of  various  cells  containing  chlorophyll,  having  found 
by  experience  that  under  certain  external  conditions  the  wliole  ap- 
paratus becomes  disintegrated  and  destroyed,  it  is  indeed  permiftrti- 
ble  to  hazard  a  conclusion  about  the  propelling  forces.  But  what 
is  altogether  puzzling  is,  how  the  active  forces  work,  how  the  sun\s 
rays  are  able  to  bring  it  about  that  the  atoms  of  the  raw  mat<.'rial 
abandon  their  previous  grouping,  become  displaced,  intermix  one 
with  another,  and  shortly  reappear  in  stable  combinations  under  a 
wholly  different  arrangement.  It  is  the  more  difficult  to  gain  a 
clear  idea  of  these  processes,  because  it  is  not  a  question  of  thai  dis- 
placement of  the  atoms  called  decomposition,  but  of  tliat  process 
which  is  known  as  combination  or  synUicsis''  (p.  377). 

I  have  made  these  quotations  from  one  of  the  greatest  Ger- 
man \vriters  on  botany^  in  order  to  show  that  a  professor  of 
the  science,  with  a  most  extensive  knowledge  of  every  aspect 
of  plant-life,  supports  the  conclusion  I  had  already  reached 
from  a  consideration  of  some  of  the  broader  phenomena  of 
animal  life  and  organisation.  In  the  last  paragraph  (pioted 
he  even  shows  that  phenomena  occur  during  the  growth  of 
the  plant,  which  are,  as  I  suggested  from  other  facts,  a»ni- 
parable  in  complexity  with  those  of  the  metamoqihosis  of  the 
higher  insects,  and,  therefore,  equally  requiring  the  agenc}* 
of  some  high  directive  power  for  an  adequate  rati(uuil  (explana- 
tion of  them. 

I  am  quite  aware  that  this  view,  of  the  earth  and  organic 
nature  having  been  designed  for  the  development  of  the  Innnan 
race,  and  further,  that  it  has  been  so  dc-iirned  that  in  the 
course  of  its  entire  cvolutlnn,  ii-;  detailed  I'eatures  and  organi- 
sation have  been  such  as  not  only  to  serve  the  purposes  of  the 


358  THE  WORLD  OF  LIFE 

whole  series  of  living  things,  but  also  in  their  final  outcome, 
to  serve  the  purposes  and  add  to  the  enjoyments  of  man,  is 
highly  distasteful  to  a  large  proportion  of  scientific  workers. 
They  think,  and  some  of  them  say,  that  it  is  a  return  to  the 
old  superstition  of  special  creation,  that  science  has  nothing 
to  do  with  first  causes,  whether  in  the  form  of  spiritual  or 
divine  agencies,  and  that  once  we  begin  to  call  in  the  aid  of 
such  non-natural  and  altogether  hypothetical  powers  we  may 
as  well  give  up  science  altogether.  In  my  early  life  I  should 
have  adopted  these  same  arguments  as  entirely  valid,  and 
should  perhaps  have  thought  of  the  advocates  of  my  present 
views  with  the  same  contemptuous  pity  which  they  now  be- 
stow upon  myself.  But,  I  venture  to  urge,  the  cases  are  not 
fairly  comparable,  because  both  their  point  of  view  and  my 
own  are  very  different  from  those  of  our  fellow-workers  of  the 
first  half  of  the  nineteenth  century. 

Let  me  recall  the  conditions  that  prevailed  then  as  compared 
with  those  of  to-day.  Then  the  opposition  was  between  science 
and  religion,  or,  perhaps  more  correctly,  between  the  enthusias- 
tic students  of  the  facts  and  theories  of  physical  science  in  the 
full  tide  of  its  efforts  to  penetrate  the  inmost  secrets  of  nature, 
and  the  more  or  less  ignorant  adherents  of  dogmatic  theology. 
]N^ow,  the  case  is  wholly  different.  Speaking  for  myself  I 
claim  to  be  as  whole-heartedly  devoted  to  modern  science  as 
any  of  my  critics.  I  am  as  fully  imbued  with  the  teachings 
of  evolution  as  they  can  be ;  and  I  still  uphold,  as  I  have  al- 
ways done,  the  essential  teachings  of  Darwinism. 

Darwin  always  admitted,  and  even  urged,  that  "  Xatural 
Selection  has  been  the  most  important  but  not  the  exclusive 
means  of  modification."  He  always  adduced  the  "  laws  of 
Growth  with  Reproduction,"  and  of  "  Inheritance  with  Varia- 
bility," as  being  fundamental  facts  of  nature,  without  which 
Natural  Selection  would  be  powerless  or  even  non-existent, 
and  which,  then  as  now,  were  and  are  wholly  beyond  explana- 
tion or  even  comprehension.  He  elaborated  his  theory  of 
Panagenesis   for  the  purpose   of  rendering  the   many   strange 


PLAA'TS  IX   UELATIOX   To   .MAX  30t) 

facts  of  inheritance  mure  nninti'lligil)lc,  l)ut  cvon  if  it  were 
IJroved  to  be  an  exact  representation  of  the  facts  it  would  not 
be  an  explanation,  because,  as  Weismann,  Kcrncr  and 
many  others  admit,  it  wuiild  n(jt  account  fur  ilic  forces, 
the  directive  agency,  and  the  orijunisiixf  jx^wer  wliich  arc  es- 
sential features  of  growth.  This  is  felt  so  strongly  bv  all  tiie 
great  workers  in  pliysiology,  that  even  Ilaeckel  has  Ix-en  driven 
to  postulate  "  mind,  soul,  or  volition,"  not  only  in  every  cell 
but  in  each  organic  molecule  or  physiological  on  it.  And  then, 
to  save  himself  from  the  slur  of  being  ^^  unscieniilic,"  an«l  of 
introducing  the  very  organising  power  he  had  <l(ridcd  when 
suggested  by  others,  he  loudly  proclaims  that  hi-  *'  soul- 
atom,"  though  it  has  "  Avill  "   is  yet  wholly   "  nnc<mscious."  ' 

I  again  urge,  therefore,  that  our  greatest  anthorities  admit 
the  necessity  of  some  mind  —  some  organising  and  directive 
power  —  in  nature;  but  they  seem  to  contemplate  merely  some 
unknown  forces  or  some  innate  rudimentarv  mind  in  cell  or 
atom.  Such  vague  and  petty  suppositions,  however,  do  not 
meet  the  necessities  of  the  problem.  I  admit  that  sueh  forces 
and  such  rudimentary  mind-power  may  an<l  imtbably  do  ex- 
ist, but  I  maintain  that  they  are  wholly  ina(h'(juate,  and  that 
some  vast  intelligence,  some  pervading  spirit  i-;  re(jnire<l  to 
guide  these  lower  forces  in  accordance  with  a  pre-ordained 
system  of  evolution  of  the  organic  world. 

If,  how^ever,  we  go  as  far  as  this,  we  must  go  farther.  If 
there  is  a  ruling  and  creative  power  to  which  the  existence 
of  our  cosmos  is  due,  and  if  we  are  its  one  and  unitpie  high- 
est outcome,  able  to  understand  and  to  make  use  of  the  forces 
and  products  of  nature  in  a  way  that  no  other  animal  lias  been 
able  to  do;  and  if,  further,  there  is  any  reasonable  probability 
of  a  continuous  life  for  us  to  still  further  develop  that  higher 
spiritual  nature  which  we  possess,  tlu^n  W(^  have  a  ])erfect 
right,  on  logical  and  scientific  grounds,  to  see  in  all  the  inti- 
nitely  varied  products  of  tli(>  animal  nn.l  vegetable  kingdoms, 

1  The  Riddle  of  the  L'niverse.  p.  04. 


3 CO  THE  WOKLD  OF  LIFE 

Avhich  we  alone  can  and  do  make  use  of,  a  preparation  for 
ourselves,  to  assist  in  our  mental  development,  and  to  fit  us 
for  a  progressively  higher  state  of  existence  as  spiritual  be- 
ings. 


CIlAl^TKK   XV  11 

THE  MYSTERY   OF   THE   CVAA. 

I  HAVE  already  given  a  short  aecount  of  the  chemical  composi- 
tion of  protoplasm  —  the  hii!;hly  complex  snhstance  now  ln-M 
to  be  the  physical  basis  of  life,  and  by  one  scIkjoI  of  biulorrists 
alleged  to  explain,  as  a  resnlt  of  that  complexity,  all  the  won- 
drous phenomena  of  growth  and  development.  1  now  propose 
to  give  a  very  brief  sketch  of  the  physical  characteristics  of  the 
living  cell,  of  its  internal  structure,  and  of  the  extraordinary 
internal  changes  it  undergoes  during  the  growth  or  reproduc- 
tion of  all  organisms. 

One  of  the  lowest  or  most  rudimentary  forms  of  life  is 
the  Amoeba,  a  living  cell,  just  visible  to  the  unaided  eye  as 
a  little  speck  of  floating  jelly.  This  creature,  being  one  of 
the  most  common  of  living  microscopic  objects,  will  have  been 
seen  by  most  of  my  readers.  At  first,  under  a  low  microscopic 
power,  it  appears  structureless,  as  it  was  for  some  time  de- 
scribed to  be,  but  with  increasing  power  and  perfection  of  the 
microscope  it  is  found  to  consist  of  three  parts  —  a  central 
body  of  a  nearly  globular  shape  slightly  darker  and  more 
granular  in  texture,  the  outer  jelly-like  mass,  and  a  small  more 
transparent  globular  portion,  which  looks  like  an  air-bubble, 
and  is  seen  to  undergo  a  slow  motion  of  contraction  and  ex- 
pansion; this  is  termed  the  "contractile  vacuole,''  which, 
when  it  has  reached  its  full  size,  p(Thaps  a  quarter  «»r  a  fifth 
of  the  whole  diameter,  suddenly  disappears,  and  after  a  little 
while  reappears  and  gradually  grows  again  to  it<  maximum 
size.  The  shape  of  the  Amceba  varies  greatly.  Sometimes  it 
is  globular  and  immovable,  but  most  fr':^quently  it  is  very  ir- 
regTilar  with  arm-like  processes  jutting  out  in  various  direc- 
tions.    By    careful    watching,    these    are    seen    t-.    increase    or 

[]G1 


362  THE  WORLD  OF  LIFE 

diminish  so  as  to  change  the  whole  shape  in  an  hour  ov  two. 
But  more  curious  is  its  power  of  absorbing  any  particles  of 
organic  matter  that  come  in  contact  with  it  by  gradually  en- 
closing them  in  its  substance,  wdiere  after  a  time  they  dis- 
appear. The  Amoebae  are  found  in  stagnant  water  full  of  or- 
ganic matter,  and  if  they  are  transferred  to  pure  waiter  they 
soon  diminish  in  size,  proving  that  they  require  food  and  can 
digest  it.  The  ''  contractile  vacuole  "  is  believed  to  have  the 
function  of  expelling  the  carbonic  acid  gas  and  other  waste 
products  of  assimilation. 

This  Amoeba  is  one  of  the  simplest  forms  of  the  lowest 
branch  of  the  animal  kingdom,  the  one-celled  animals  or 
Protozoa ;  all  other  animals  being  classed  as  Metazoa,  as  they 
are  entirely  built  up  of  separate  cells,  which  in  all  the  more 
complex  forms  are  countless  millions  in  number.  Every  part 
of  our  bodies,  from  blood  to  muscles  and  nerves,  from  bones 
to  skin,  hair,  and  nails,  is  alike  constructed  of  variously  modi- 
fied cells. 

It  might  be  thought  that  animals  consisting  of  single  cells 
could  not  be  very  numerous  or  very  differently  organised. 
Yet  they  are  grouped  into  five  classes,  the  first,  Rhizopoda, 
comprising  not  only  many  kinds  of  Amoeba?,  but  the  beauti- 
ful Foraminifera,  whose  exquisite  shells  are  such  favourite 
microscopic  objects.  They  are  single  amoeboid  cells  which  yet 
have  the  power  either  of  building  up  shells  of  small  inorganic 
particles,  or  of  secreting  the  more  beautiful  shells  which  seem 
to  mimic  the  forms  of  those  of  the  higher  Mollusca.  The 
fossils  called  Xummulites  were  Foraminifera  with  flat  coiled 
shells,  forming  great  masses  of  Eocene  limestone.  They  are 
the  largest  of  all,  some  equalling  a  half-crown  in  size. 
Radiolaria  are  rhizopods  having  a  beautiful  siliceous  skele- 
ton, and  often  living  in  colonies.  Another  class,  the  Mastigo- 
phora,  have  extremely  varied  shapes,  often  like  sea-weed  or 
flowers,  having  long,  slender,  whip-like  processes.  These  and 
hundreds  of  other  strange  forms  are  still  essentially  single 
cells,  though  often  grouped  together  for  a  time,  and  they  all 


MYSTERY  OF  THE  CELL  3G3 

increase  either  by  division  or  by  giving  off  buds,  which  ra[)i(lly 
grow  into  the  perfect  form. 

The  remarkable  thing  in  all  these  one-celled  creatures  is 
that  they  so  much  resemble  higher  animals  without  any  of  their 
organs.  The  writer  of  the  article  Cell  iu  Chambers's 
Encyclopaedia  says:  ''The  absence  of  a  circulating  fluid,  of 
digestive  glands,  nerves,  sense-organs,  lungs,  kidneys,  an<l  the 
like,  does  not  in  any  way  restrict  the  vital  functions  of  a 
unicellular  organism.  All  goes  on  as  usual,  only  with  gi-eater 
chemical  complexity,  since  all  the  different  processes  have  but 
a  nnit-mass  of  protoplasm  in  which  they  occur.  The  physi- 
ology of  independent  cells,  instead  of  being  very  simple,  must 
be  very  complex,  just  because  structure  or  differentiation  is 
all  but  absent."  All  the  one-celled  animals  and  plants  go 
through  a  series  of  changes  forming  the  cycle  of  their  life- 
history.  Beginning  as  a  nearly  globnlar  quiescent  cell,  they 
change  in  form,  put  forth  growths  of  various  kinds,  then  be- 
come quiescent  again  and  give  rise  to  new  cells  by  subdivi- 
sion or  budding. 

This  fundamental  fact,  that  all  organic  life-forms  begin 
with  a  cell  and  are  wholly  built  up  either  by  outgrowths  of 
that  one  cell  or  by  its  continued  division  into  myriads  of 
modified  cells  of  which  all  the  varied  organs  of  living  things 
are  exclusively  formed,  was  first  established  about  the  year 
1840,  and  was  declared  by  the  eminent  naturalist  Louis 
Agassiz  to  be  "  the  greatest  discovery  in  the  natural  sciences 
in  modern  times."  The  cell  is  now  defined  as  ""  a  nucleated 
unit-mass  of  living  protoplasm."  It  is  not  a  mere  particle 
of  protoplasm,  but  is  an  organised  structure.  We  are  again 
compelled  to  ask,  Organised  by  what?  Huxley,  as  we  have 
seen  in  Chapter  XV.,  tells  us  that  life  is  the  organising  power ; 
Kerner  termed  it  a  vital  force ;  Haeckel,  a  cell-soul,  but  un- 
conscious, and  he  postulated  a  similar  soul  in  each  organic 
molecule,  and  even  in  each  atom  of  matter.  But  none  of  these 
verbal  suggestions  go  to  the  root  of  the  matter;  none  of  thcui 
suppose  more   than    some   ^'  force,"    and    force   is   a   cause   of 


366  THE  WOKLD  OF  LIFE 

cell-substance.  This  serves  to  divide  the  chromatin  elements  into 
two  equal  parts,  to  separate  the  resulting  halves  from  one  another, 
and  to  arrange  them  in  a  regular  manner.  At  the  opposite  poles 
of  the  longitudinal  axis  of  the  nucleus  two  clear  bodies  —  the 
*'  centrosomes/"  each  surrounded  by  a  clear  zone  —  the  so-called 
''  sphere  of  attraction  '^ — now  becomes  visible  (A  to  D,  cs).  They 
possess  a  great  power  of  attraction  over  the  vital  particles  of  the 
cell,  so  that  these  become  arranged  around  them  in  a  series  of 
rays.  At  a  certain  stage  in  the  preparation  for  division,  the  soft 
protoplasmic  substance  of  the  cell-body  as  well  as  of  the  nucleus 
gives  rise  to  delicate  fibres  or  threads ;  these  fibres  are  motile,  and, 
after  the  disappearance  of  the  nuclear  membrane,  seize  the  chromo- 
somes —  whether  these  have  the  form  of  loops,  rods,  or  globular 
bodies  —  with  wonderful  certainty  and  regularity,  and  in  such  a 
way  that  each  element  is  held  on  either  side  by  several  threads  from 
either  pole  (B,  C).  The  chromatin  elements  thus  immediately  be- 
come arranged  in  a  fixed  and  regular  manner,  so  that  they  all  come 
to  lie  in  the  equatorial  plane  of  the  nucleus,  which  we  may  con- 
sider as  a  spherical  body." 

!N^ow  follows  another  and  even  more  remarkable  stage  in 
the  process,  which  is  thus  described : 

"  The  chromatin  elements  then  split  longitudinally,  and  thus 
become  doubled  (B),  as  Fleming  first  pointed  out.  It  must  be 
mentioned  that  this  splitting  is  not  caused  by  a  pull  from  the  pole 
threads  (spindle  threads),  which  attach  themselves  to  the  chroma- 
tin-rods  on  both  sides ;  the  division  arises  rather  from  forces  acting 
in  the  rods  themselves,  as  is  proved  by  the  fact  that  they  are  often 
ready  to  divide,  or  indeed  have  already  done  so,  some  time  before 
their  equatorial  arrangement  has  taken  place  by  means  of  these 
threads. 

"  The  splitting  is  completed  by  the  two  halves  being  gradually 
drawn  further  apart  towards  the  opposite  poles  of  the  nuclear 
spindle,  until  they  finally  approach  the  centre  of  attraction  or 
centrosome  (D),  which  has  now  fulfilled  its  object  for  the  present, 
and  retires  into  the  obscuritv  of  the  cell-substance,  onlv  to  become 
active  again  at  the  next  cell-division.  Each  separated  half  of  the 
nucleus   now    constitutes    a    daughter-nucleus,    in   which    it    (the 


MYSTERY  OF  THE  CELL  367 

chromatin)  immediately  breaks  up,  and  Ixvomps  scattered  in  the 
form  of  minute  granules  in  tlic  delicate  nuclear  network,  so  that 
finally  a  nucleus  is  formed  of  exactly  the  same  structure  as  that 
with  which  we  started." 

Weismann  then  discusses  and  explains  the  meaning  of  this 
strange  phenomenon.     He  says: 

"  It  is  evident,  as  Wilhelm  Koux  was  the  first  to  point  out,  that 
the  whole  complex,  but  wonderfully  exact,  apparatus  for  the  division 
of  the  nucleus  exists  for  the  purpose  of  dividing  the  chromatin 
substance  in  a  fixed  and  regular  manner,  not  merely  quantitatively, 
but  also  in  i-espect  of  the  different  qualities  which  must  be  contained 
in  it.  So  complicated  an  apparatus  wouhl  have  been  unnecessary 
for  the  quantitative  division  only.  W,  however,  the  chromatin  sub- 
stance is  not  uniform,  but  is  made  up  of  several  or  many  different 
qualities,  each  of  which  has  to  be  divided  as  nearly  as  possible  into 
halves,  or  according  to  some  definite  rule,  a  better  apparatus  could 
not  be  devised  for  the  purpose.  On  the  strength  of  this  argument 
we  may,  therefore,  represent  the  hereditary  substance  as  consisting 
of  different  qualities.  .  .  .  The  statement  that  this  substance 
is  the  hereditary  substance  can,  therefore,  hardly  be  considered  as 
an  hypothesis  any  longer."  ^ 

After  some  further  discussion  of  the  views  of  other  writers, 
he  goes  on  to  show  that  the  chromatin  substance  is  not  only 
contained  in  the  germ-cells,  but  also  in  all  the  cells  of  the 
entire  organism  in  each  phase  of  its  development,  which  is 
effected  bv  the  constant  division  of  the  cells  and  their  nuclei, 
the  chromatin  continuing  to  grow  during  the  whole  time.  But 
in  the  body  it  enters  on  a  long  and  complex  process  of  growth, 
so  as  to  build  up  the  substance  of  all  the  varied  organs  and 
tissues,  and  also  for  the  repair  or  renovation  of  these  various 
tissues  as  they  require  it.  He  illustrates  the  successive 
changes  which  he  supposes  the  chromatin  to  bring  about,  and 
for  which  purpose  it  is  so  accurately  divided  and  subdivided 
from  the  very  beginning,  in  the  following  inissage: 

1  The  Gcnn-Plasm,  p.  29. 


368  THE  WORLD  OF  LIFE 

"Even  the  two  first  clanghter-cells  (E)  which  result  from  the 
division  of  the  egg-cell  give  rise  in  many  animals  to  totally  different 
parts.  One  of  them,  by  continued  cell-division,  forms  the  outer 
germinal  layer,  and  eventually  all  the  organs  which  arise  from  it, 
e.  g.  the  epidermis,  central  nervous  system,  and  sensory  cells ;  the 
other  gives  rise  to  the  inner  germinal  layer  and  the  organs  derived 
from  it  —  the  alimentary  system,  certain  glands,  etc.  The  conclu- 
sion is  inevitable  that  the  chromatin  determining  these  hereditary 
tendencies  is  different  in  the  very  first  two  daughter-cells." 

Later  on  he  shows  in  great  detail  how^  similar  but  even 
more  complex  changes  take  place  in  the  newly  fertilised  germ- 
cell  in  v^hich  the  male  and  female  elements  are  combined,  for 
the  purpose  of  bringing  about  the  accurate  partition  of  these 
elements  in  all  the  cells  which  arise  from  them  by  subdivision, 
thus  rendering  possible  the  production,  in  all  future  genera- 
tions, of  males  and  females  in  nearly  equal  proportions.  He 
also  shows  that  there  is  a  special  provision  for  the  produc- 
tion of  slight  variations  in  successive  generations  in  a  way  too 
complex  to  be  explained  here.  This,  of  course,  is  largely 
speculation,  but  it  is  based  at  every  step  on  observed  facts 
in  the  processes  of  fertilisation  and  cell-division.^ 

In  Professor  J.  Arthur  Thomson's  most  valuable  and  il- 
luminating work  on  Heredity,  in  which  he  impartially  ex- 
pounds the  theories  and  discoveries  of  all  the  great  physio- 
logical writers  of  the  world,  he  gives  a  very  high,  if  not  the 
highest,  place  to  those  of  Weismann.  I  will  therefore  quote 
from  his  volume  Weismann's  latest  short  statement  of  his 
hypothesis  as  to  the  nature  of  the  germ-plasm ;  and  also  Pro- 

1  The  reader  will  see  that  the  diagrams  referred  to  in  Weisraann's  state- 
ments, quoted  above,  do  not  seem  to  represent  accurately  what  he  says. 
They  must,  therefore,  be  taken  as  "  diagrams  "  only,  not  detailed  "  figures  " 
of  what  is  seen,  which  are  often  so  complex  that  it  is  difficult  to  follow 
the  essential  details.  They  are  for  the  purpose  of  indicating  definite  stages 
in  the  process  of  the  development  of  cells  up  to  the  first  cell-division. 
The  small  letters  (jd)  are  not  referred  to  in  Weismann's  explanation  on 
the  plate  itself,  nor  in  his  description  of  what  happens.  But  these  letters 
evidently  mean  "  idants,"  as  explained  in  Professor  J.  A.  Thomson's  sum- 
mary of  Weismann's  theory  at  p.  20. 


MYSTEP.Y  OF  THE  CELL  309 

fessor  Thomson's  very  short  summary  of  it,  giving  an  explana- 
tion of  Weismann's  special  terminology.  Weismann's  state- 
ment is  as  follows: 

"  The  germ-substance  owes  its  marvellous  power  of  development 
not  only  to  its  chemico-physical  constitution,  but  to  the  fact  that  it 
consists  of  many  different  kinds  of  primary  constituents,  that  is, 
of  groups  of  vital  units  equipped  witli  the  forces  of  life,  and  capa- 
ble of  interposing  actively  and  in  a  specific  manner,  but  also 
capable  of  remaining  latent  in  a  passive  state  until  they  are  af- 
fected by  a  liberating  stimulus,  and  on  this  account  able  U)  inter- 
pose successfully  in  development.  The  germ-cell  cannot  be  merely 
a  simple  organism;  it  must  be  a  fabric  made  up  of  many  different 
organisms  or  units  —  a  microcosm."  ^ 

And  Professor  J.  A.  Thomson's  Summary  of  Weismann's 
mechanics  of  the  germ-plasm  is  as  follows : 

Summary 

"  The  physical  basis  of  inheritance  —  the  germ-plasm  —  is  in 
the  chromatin  of  the  nucleus  of  the  germ-cell. 

"  The  chromatin  takes  the  form  of  a  definite  number  of  chromo- 
somes or  idants  (Fig.  110,  B,  C,  D,  id). 

"  The  chromosomes  consist  of  ids,  each  of  which  contains  a 
complete  inheritance. 

"  Each  id  consists  of  numerous  primary  constituents  or  deter- 
minants. 

"  A  determinant  is  usually  a  group  of  hiophors,  the  minutest 
vital  units. 

"  The  biophor  is  an  integrate  of  numerous  chemical  molecules." 

In  the  preceding  Summary  I  have  italicised  the  technical 
terms  invented  by  Weismann  for  the  different  stages  of  what 
may  be  called  the  mechanical  explanation  of  heredity  by 
means  of  the  successive  changes  observed  in  the  growing  and 
dividing  germ-cells.  But,  as  he  himself  admits,  it  explains 
nothing  Avithout  taking  for  granted  the  essential  phenomena  of 
life  —  nutrition,  assimilation,  and  growth;  and  these  are  ad- 
mitted to  be  to  this  day  quite  unexplainable. 

iThe  Evolution  Tlipory,  trans,  by  J.  A.  Tlionison.   1004.  vol.  i.  p.  402. 


370 


THE  WORLD  OF  LIFE 


chr. 


^ii 


ciftr 


J) 


Fig.   110. —  Diagram  of  Nuclear 
Division. 

A.  Cell  with  nucleus  (n)  and  centro- 
somes  {cs)  preparatory  to  division. 
The  chromatin  has  become  thick- 
ened so  as  to  form  a  spiral  thread 
(c/ir). 

B.  The  nuclear  membrane  has  dis- 
appeared. Delicate  threads  radiate 
from  the  chromosomes,  and  form 
the  "nuclear  spindle,"  and  the 
equator  of  which  eight  chromo- 
somes or  nuclear  loops  (chr=Jd) 
are  arranged;  these  have  been 
formed  by  the  spiral  thread  of 
chromatin  in  A  becoming  broken 
up. 

C.  The  chromosomes  have  each  be- 
come split  longitudinally  into  two, 
and   are    about   to   be   drawn   apart 

by  means  of  the  spindle  threads.      (For  clearness  four  only  of  the  eight  chromo- 
somes are  shown.) 

D.  The  daughter-loops  pass  towards  the  poles  of  the  spindle. 

E.  The   cell  has  divided,   each  new   cell   containing   a   centrosome   and  eight  nuclear 
loops. 

(From  Weismann's  Germ-Plasm,  by  permission  of  Walter  Scott,  Ltd.) 


MYSTERY  OF  THE  CELJ.  371 

But  the  very  first  step  of  this  process  of  ^^rowtli  —  the  di- 
vision of  the  germ-cells,  as  descrihed  by  Weisniann  himself 
and  illustrated  by  his  diagrams  —  is,  as  he  himself  almost  ad- 
mits, equally  inexplicable.  He  speaks  of  a  *'  complex,  but 
wonderfully  exact,  apparatus  for  the  division  of  the  nucleus," 
of  the  purpose  of  that  division  being  qualitative  as  well  as 
quantitative,  and  of  its  evident  adnptailon  to  the  building  up 
of  the  future  body,  with  all  its  marvellous  complexities,  co- 
ordinations, and  powers.  So  that  the  farther  we  go  in  this 
bewildering  labyrinth,  as  expounded  in  his  wnrlcs,  in  those  of 
Professor  Thomson,  of  Max  ^^erworu,  or  in  such  general  works 
as  Parker  and  Haswell's  Text-Book  of  Zoology,  the  more  hope- 
lessly inadequate  do  we  find  the  claims  of  Ilaeckel,  Verworu, 
and  their  school  to  having  made  any  approach  whatever  to  a 
solution  of  "  the  riddle  of  the  universe,''  so  far  as  regards  its 
crowning  problem,  the  origin  and  development  of  life. 

The  Plant  Cell 

So  far  I  have  taken  the  facts  as  to  cell-division  from  the 
works  of  zoologists  only ;  but  almost  exactly  the  same  phe- 
nomena have  been  found  to  occur  in  plants,  though  they  seem 
to  have  been  rather  more  difficult  to  detect  and  unravel.  In 
Professor  A.  Kerner's  Katural  History  of  Plants,  already 
quoted,  he  gives  the  following  short  description  of  cell-di- 
vision : 

Wlien  a  protoplast  living  in  a  cell-cavity  is  about  to  divide  into 
two,  the  process  resulting  in  division  is  as  follows :  —  The  nucleus 
places  itself  in  the  middle  of  its  cell,  and  at  first  characteristic  lines 
and  streaks  appear  in  its  substance,  making  it  look  like  a  ball  made 
up  of  little  threads  and  rods  pressed  together.  Tliese  threads 
gradually  arrange  themselves  in  positions  corresponding  to  the 
meridian  lines  upon  a  globe:  but  at  the  place  where  on  a  globe 
the  equator  would  lie,  there  then  occurs  suddenly  a  cleavage  of  tlie 
nucleus  —  a  partition  wall  of  cellulose  is  interposed  in  the  gap.  and 
from  a  single  cell  we  have  now  produced  a  pnir  of  cells  ■'  (vol.  i. 
p.  48). 


372  THE  WOELD  OF  LIFE 

But  later  on  we  have  a  much  fuller  description,  illustrated 
by  four  diagrammatic  figures  of  the  dividing  cell,  which  show 
that  the  process  in  plants  is  substantially  identical  with  that 
described  and  figured  already  from  Weismann  (vol.  i.  p. 
581).  This  is  most  instructive,  because  it  shows  the  absolute 
identity  of  the  fundamental  mechanics  of  life  in  the  animal 
and  vegetable  kingdoms,  though  their  ultimate  developments 
are  so  wonderfully  diverse. 

Another  interesting  point  is  that,  just  as  Weismann  has 
stated,  there  is  an  identity  in  the  number  of  certain  elements 
in  the  cell  for  each  species.     Kemer's  statement  is : 

"  For  every  species  of  plant  the  number,  size,  and  shape  of  the 
bodies  arising  in  the  interior  of  a  cell  by  division  are  quite  definite, 
though  they  vary  from  species  to  species.  In  the  cell-chambers  of 
some  species  several  thousand  minute  protoplasmic  bodies  arise. 
In  others,  again,  the  number  is  very  limited.  If  the  number  is 
large  the  individual  masses  are  exceedingly  small,  and  can  only  be 
recognised  when  very  greatly  magnified.  If  the  number  is  limited 
the  divided  portions  are  comparatively  large.  The  shape  of  the 
structure  is  exceedingly  various.  Some  are  spherical,  elliptical,  or 
pear-shaped;  others  elongated,  fusiform,  filamentous,  or  spatulate; 
some  are  straight,  others  are  spirally  twisted,  and  many  are  drawn 
out  into  a  thread;  others  are  provided  over  the  whole  surface  with 
short  cilia;  others,  again,  with  a  crown  of  cilia  at  a  particular 
spot,  or  with  only  a  single  pair  of  long  cilia.  In  the  majority  of 
cases  the  small  bodies  exhibit  active  movements;  but  sooner  or 
later  they  come  to  rest,  and  then  assume  another  shape  or  fuse 
with  another  protoplasmic  body." 

Referring  to  the  theory  that  the  structure  of  each  plant 
is  due  to  the  specific  constitution  of  the  protoplasm  of  the 
species,  Kerner  says : 

"  What  it  does  not  account  for  is  the  appropriate  manner  in 
which  various  functions  are  distributed  among  the  protoplasts  of 
a  cell-community ;  nor  does  it  explain  the  purposeful  sequence  of 
diiferent  operations  in  the  same  protoplasm  without  any  change 
in  the  external  stimuli;  the  thorough  use  made  of  external  ad- 


MYSTERY  OF  THE  CELL  37U 

vantages;  the  resistance  to  injurious  influences;  the  avoidance  or 
encompassing  of  insuperable  obstacles ;  the  punctuality  with  which 
aU  the  functions  are  performed ;  the  periodicity  which  occurs  with 
the  greatest  regularity  under  constant  conditions  of  environment ; 
nor,  above  all,  the  fact  that  the  power  of  discharging  all  the  op- 
erations requisite  for  growth,  nutrition,  renovation,  and  multipli- 
cation is  liable  to  be  lost.  We  call  the  loss  of  this  power  the  death 
of  the  protoplasm"  (vol.  i.  p.  51). 

Growth  hy  Cell-Division:     What  it  Implies 

As  the  account  now  given  of  the  most  recent  discoveries  as 
to  what  actually  takes  place  in  the  living  cell  preparatory  to 
its  division  and  subdivision,  wliich  are  *\  3  very  first  steps  in 
the  growth  or  building  up  of  the  highly  complex 'and  perfect 
animal  or  plant,  is  very  technical,  and  will  be  perhaps  unin- 
telligible to  some  of  my  readers,  I  will  now  give  a  very  short 
statement  of  the  process  with  a  few  illustrations,  and  remarks 
as  to  w^hat  it  all  really  means,  and  how"  alone,  in  my  opinion, 
it  can  possibly  be  explained. 

The  egg  is  a  single  cell  with  a  special  central  point  or  organ, 
called  the  nucleus,  and  it  is  this  nucleus  which  makes  the  cell 
a  germ-cell.  That  this  is  so  has  been  proved  in  many  ways, — 
in  plants  by  grafting  or  hudding,  where  the  ilower-bud  which 
contains  a  germ-cell,  when  inserted  in  the  bark  of  a  differ- 
ent variety,  and  sometimes  a  different  species  of  plant,  repro- 
duces the  exact  kind  of  flower  or  fruit  that  characterised  the 
tree  or  bush  the  bud  was  taken  from,  not  that  of  the  plant  of 
which  it  now^  forms  a  part,  and  whose  sap  forms  its  nourish- 
ment. 

Again,  Professor  Boveri  deprived  an  Qgg  of  a  species  of 
sea-urchin  {Echinus  microtuherculatus)  of  its  nucleus,  and 
then  fertilised  the  egg  with  the  spermatozoa  of  anotlier  species 
{Sphcerechiiiu^  qranidaris).  The  egg  so  treated  developed 
larva?  with  the  true  characters  of  the  latter  species  only,  so 
that  the  main  substance  of  the  egg  provided  nutriment  for 
the  offspring,  but  did  not  transmit   to   it   any  of  it^  parental 


a7i  THE  WOELD  OF  LIFE 

characters.  A  similar  illustration,  at  a  later  period  of  life,  is 
that  of  an  infant  Avhich  from  birth  is  fed  on  cow's  milk,  yet, 
if  it  lives,  possesses  only  human  characteristics. 

This  nucleus^,  therefore,  which,  when  fertilised,  has  such 
marvellous  powers  and  properties,  is  tlie  seat  of  heredity  and 
development.  What  is  it  that  gives  it  this  power  ?  What 
is  the  agency  that  sets  in  motion  a  whole  series  of  mechanical, 
chemical,  and  vital  forces,  and  guides  them  at  every  step  to 
their  destined  end  ?  Again,  I  urge,  let  us  consider  what  we 
have  to  explain.  The  matter  of  the  fertilised  egg  is  the  mil- 
lionfold  complex  substance  called  protoplasm.  It  is  also 
mainly  living  protoplasm.  AVhat  power  gave  it  life  ?  It  is 
also  (in  its  essential  part,  the  nucleus)  already  highly  differ- 
entiated —  it  is  organised  'protoplasm.  What  poiver  organ- 
ised it  ?  It  is  a  liquid  or  semi-liquid  substance  with  slight 
cohesion ;  it  gradually  forms  a  cell,  which  divides  and  sub- 
divides, till  at  a  certain  point  the  globular  mass  or  layer  of  cells 
bends  inward  upon  itself,  forming  a  hollow  sac  with  outer  and 
inner  walls.  What  power  determines  the  cell-mass  to  take 
this  or  other  well-defined  shapes  ?  Then,  as  cell-division  and 
specialisation  go  on,  the  rudiments  of  muscle  and  bone  are 
formed  with  totally  distinct  properties  —  the  one  with  im- 
mense contractility  and  tensile  strength,  the  other  with  great 
hardness  and  rigidity.  Who  or  what  guides  or  determines 
the  atoms  of  the  protoplasmic  molecules  into  these  new  comibi- 
nations  chemically,  and  new  structures  mechanically  ?  —  com- 
binations and  structures  which  all  the  chemists  and  physicists 
of  the  world  are  powerless  to  produce  even  when  they  have  the 
ready-formed  protoplasm  given  them  to  start  with  ?  Then  as 
the  process  goes  on  in  an  ever-increasing  complexity  which 
baffles  the  microscope  of  the  observer  to  follow,  never  diverg- 
ing at  any  one  point  from  the  precise  mode  of  change  which 
alone  leads  on  to  the  completed  living  organism,  we  are  asked 
to  be  satisfied  with  millions  of  ^^  gemmules,"  "  fundamental 
units,"  "  determinants,"  etc.,  which  actually  do  build  up  the 


MYSTEKY  OF  THE  CELL  375 

living  body  of  each  organism  in  a  prescribed  and  lUK-liangcable 
sequence  of  events.  But  this  orderly  process  is  quite  unintel- 
ligible without  some  directive  org,anising  power  constantly  at 
work  in  or  upon  every  chemical  atom  or  physical  niolcculv  of 
the  whole  structure,  as  one  after  another  they  are  brought  to 
their  places,  and  built  in,  as  it  were,  to  the  structure  of  every 
tissue  of  every  organ  as  it  takes  form  and  substance  in  tlie 
fabric  of  the  living,  moving,  and,  in  the  case  of  animals,  sensi- 
tive creation. 

I  will  conclude  this  short  sketch  of  cell-life  and  its  mystery, 
with  a  picturesque  account  of  one  striking  example  in  the  ani- 
mal world,  from  Professor  Lloyd  Morgan's  illuminating  vol- 
ume. 

There  is,  perhaps,  no  more  wonderful  instance  of  rapid  and 
vigorous  growth  than  the  formation  of  the  antlers  of  deer.  These 
splendid  weapons  and  adornments  are  shed  every  year,  in  the 
spring,  when  they  are  growing,  they  are  covered  over  with  a  dark 
skin  provided  with  short,  line,  thick-set  hair,  and  technically  termed 
"  the  velvet.'^  If  you  lay  your  hand  on  the  growing  antler,  you  will 
feel  that  it  is  hot  with  the  nutrient  blood  that  is  coursing  beneath 
it.  It  is,  too,  exceedingly  sensitive  and  tender.  An  army  of  tens 
of  thousands  of  busv  livinor  cells  is  at  work  beneath  that  velvet 
surface,  building  the  bony  antlers,  preparing  for  the  battles  of 
autunm.  Each  minute  cell  knows  its  work,  and  does  it  for  llie 
general  good  —  so  perfectly  is  the  body  knit  into  an  organic  whole. 
It  takes  up  from  the  nutrient  blood  the  special  materials  it  requires  ; 
out  of  them  it  elaborates  the  crude  bone-stuff,  at  first  soft  as  wax, 
but  ere  long  to  become  as  hard  as  stone;  and  then,  having  done  iis 
work,  having  added  its  special  morsel  to  the  fabric  of  the  antler,  it 
remains  imbedded  and  immured,  buried  beneath  the  bone  prodiRis 
o":  its  successors  or  descendants.  No  hive  of  Ijccs  is  busier  or  more 
replete  with  active  life  than  the  antler  of  a  stag  as  it  grows  ])eneatli 
the  soft  warm  '  elvet.  And  thus  are  built  up  in  the  eoiirsp  of  a  few 
weeks  those  splendid  "beams"  with  their  "  tynos ''  and  "snags," 
which,  in  the  case  of  the  wapiti,  even  in  the  continomont  of  the 
Zoological  Gardens,  may  reach  a  weight  of  thirty-two  ]>ounds,  and 


376  THE  WOKLD  OF  LIFE 

which,  in  the  freedom  of  the  Eocky  Mountains,  may  reach  such  a 
size  that  a  man  may  walk  without  stooping  through  the  archway 
made  by  setting  up  upon  their  points  tlie  shed  antlers. 

In  the  eastern  European  forests  the  horns  of  the  red  deer 
reach  a  w^eight  of  74  pounds,  while  in  the  recently  extinct  Irish 
elk  the  large,  broadly  palmated  horns  sometimes  reached  an 
expanse  of  11  feet.  These  remarkable  weapons  were  devel- 
I  oped  both  for  combats  between  the  males  and  as  a  means  of  pro- 
\  tecting  the  females  and  young  from  enemies.  As  organic  out- 
growths they  are  extremely  simple  when  compared  with  the 
feathers  of  the  bird  or  the  scales  of  a  butterfly's  wing;  yet  as 
exemplifying  the  need  for  some  guiding  power,  exerted  upon 
the  individual  cells  which  carrv  out  the  work  with  such  won- 
derful  precision  every  year,  they  are  equally  striking.  The 
blood,  we  know,  furnishes  the  materials  for  every  tissue  in  the 
body;  but  here  a  large  mass  of  bony  matter,  covered  with  a 
thin  skin  and  dense  hair,  is  rapidly  built  up,  to  a  very  definite 
form  in  each  species;  then  the  skin  and  hair  cease  growing 
and  fall  away,  while  the  horns  persist  for  nearly  a  year,  when 
they,  too,  fall  off  and  are  again  renewed. 

Concluding  Remarks  on  the  Cell-Prohlem 

The  very  short  account  I  have  now  given  of  w^hat  is  known 
of  the  essential  nature,  the  complex  structure,  and  the  alto- 
gether incomprehensible  energies  of  these  minute  unit-masses 
of  living  matter,  the  cells  —  so  far  as  possible  in  the  very  words 
of  some  of  the  most  recent  authorities  —  must,  I  think,  con- 
vince the  reader  that  the  persistent  attempts  made  by  llaeckel 
and  Yerw^oru  to  minimise  their  marvellous  powers  as  mere  re- 
sults of  their  complex  chemical  constitution,  are  w^holly  un- 
availing. They  are  mere  verbal  assertions  which  prove  noth- 
ing; w^hile  they  afford  no  enlightenment  wdiatever  as  to  the 
actual  causes  at  work  in  the  cells  leading  to  nutrition,  to  growth, 
and  to  reproduction. 

Very  few  of  the  workers  who  have  made  known  to  us  the 


MYSTEKY  OF  THE  CELL  377 

strange  phenomena  of  cell-life  in  liie  Protozoa,  and  of  cell- 
division  in  the  higher  animals  and  plants,  seem  to  think  any- 
thing about  the  hidden  causes  and  forces  at  work.  They  are 
so  intensely  interested  in  their  discoveries,  and  in  following 
out  the  various  chani^es  in  all  their  ramitications,  that  tliev 
have  no  time  and  little  inclination  to  do  more  than  add  con- 
tinually to  their  knowledge  of  the  facts.  And  if  one  attempts 
to  read  through  anv  ffood  text-book  such  as  Parker  and  Has- 
well's  Zoology,  or  J.  Arthur  Thomson's  Heredity,  it  is  easy  to 
understand  this.  The  complexities  of  the  lower  forms  of  life 
are  so  overwhelming  and  their  life-histories  so  mysterious,  and 
yet  they  have  so  much  in  common,  and  so  many  cross-affinities 
among  the  innumerable  new  or  rare  species  continually  being 
discovered,  that  life  is  not  long  enough  to  investigate  the  struc- 
ture of  more  than  a  very  small  number  of  the  known  forms. 
Hence  very  few  of  the  writers  of  such  books  express  any  opin- 
ion on  those  fundamental  problems  which  Haeckel  and  his  fol- 
low^ers  declare  to  have  been  solved  by  them.  All  questions  of 
antecedent  purpose,  of  design  in  the  course  of  development,  or 
of  any  organising,  directive,  or  creative  mind  as  the  funda- 
mental cause  of  life  and  organisation,  are  altogether  ignored, 
or,  if  referred  to,  are  usually  discussed  as  altogether  imscien- 
tific  and  as  showing  a  deplorable  want  of  confidence  in  the 
powers  of  the  human  mind  to  solve  all  terrestrial  problems. 

If,  as  I  have  attempted  to  do  here,  we  take  a  broad  and  com- 
prehensive view  of  the  vast  world  of  life  as  it  is  spread  out  be- 
fore us,  and  also  of  that  earlier  world  which  goes  back,  and 
ever  further  back,  into  the  dim  past  among  the  relics  of  pre- 
ceding forms  of  life,  tracing  all  living  things  to  more  gen- 
eralised and  usually  smaller  forms;  still  going  back,  till  one 
after  another  of  existing  families,  orders,  and  even  classes,  of 
animals  and  plants  either  cease  to  appear  ur  are  represented 
only  by  rudimentary  forms,  often  of  types  tpiite  unknown  to 
us;  we  meet  with  ever  greater  and  greater  ditiiculties  in  dis- 
pensing with  a  guiding  purpose  and  an  immanent  creative 
powder. 


378  THE  WOKLD  OF  LIFE 

For  we  are  necessarily  led  back  at  last  to  the  beginnings  of 
life  —  to  that  almost  infinitely  remote  epoch  myriads  of  years 
before  the  earliest  forms  of  life  we  are  acquainted  with  had 
left  their  fragmentary  remains  in  the  rocks.  Then,  at  some 
definite  epoch,  the  rudiments  of  life  must  have  appeared.  But 
whenever  it  began,  whenever  the  first  vegetable  cell  began  its 
course  of  division  and  variation ;  and  when,  very  soon  after, 
the  animal  cell  first  appeared  to  feed  upon  it  and  be  developed 
at  its  exj)ense, —  from  that  remote  epoch,  through  all  the  ages 
till  our  own  day,  a  continuous,  never-ceasing,  ever-varying 
process  has  been  at  work  in  the  two  great  kingdoms,  vegetal 
and  animal,  side  by  side,  and  always  in  close  and  perfect 
adaptation  to  each  other. 

Myriads  of  strange  forms  have  appeared,  have  given  birth 
to  a  variety  of  species,  have  reached  a  maximum  of  size,  and 
have  then  dwindled  and  died  out,  giving  way  to  higher  and 
better-adapted  creatures ;  but  never  has  there  been  a  complete 
break,  never  a  total  destruction,  even  of  terrestrial  forms  of 
life  ;  but  ever  and  ever  they  became  more  numerous,  more  varied, 
more  beautiful,  and  hetler  adapted  to  tJie  wants,  the  'material 
'progresSj,  the  higher  enjoyments  of  mankind. 

The  whole  vast  series  of  species  of  plants  and  animals,  with 
all  their  diversities  of  form  and  structure,  began  at  the  very 
dawn  of  life  upon  the  cooling  earth  with  a  single  cell  (or  with 
myriads  of  cells)  such  as  those  whose  structure  and  properties 
we  have  here  been  considering;  and  every  single  individual  of 
the  myriads  of  millions  Avhich  have  ever  lived  upon  the  earth 
have  each  begun  to  be  developed  from  a  similar  but  not  idm- 
tical  cell ;  and  all  the  possibilities  of  all  their  organs,  and 
structures,  and  secretions,  and  organic  products  have  arisen  out 
of  such  cells;  and  we  are  asked  to  believe  that  tliese  cells  and 
all  their  maiwellous  outcome  are  the  result  of  the  fortuitous 
clash  of  atoms  with  the  help  of  '^  an  unconscious  cell-soul  of 
the  most  primitive  and  rudimentary  kind !  " 


MYISTEKV   OF  THE  CELL  3Tti 

The  Fallacy  of  Eternity  as  an  Explanation  of  Evolution 

It  may  perhaps  not  be  out  of  place  here  to  deal  with  what 
seems  to  me  to  be  one  of  the  common  philosophical  fallacies  of 
the  present  day,  the  iilea  that  you  can  get  over  the  difficulty 
of  requiring  any  supreme  mind,  any  author  <jf  the  cosmos,  by 
assuming  that  it  had  no  beginning  —  that  it  has  existed,  with 
all  its  forces,  energies,  and  laws,  from  all  eternity,  and  thai  it 
^vill  continue,  to  exist  for  all  eternity. 

I  have  already  quoted  llaeckel  and  some  others  on  this 
point.  I  will  now  give  a  similar  statement  by  two  writers  of 
to-day.  Dr.  Saleeby  in  an  article  on  The  Life  of  the  Uni- 
verse, in  The  Academy  (March  25,  1905),  after  discussing 
the  theory  of  dissipation  of  energy,  the  infinity  of  the  uui- 
verse,  the  littleness  of  man,  and  other  matters,  with  his  usual 
clearness  and  vigour,  concludes  with  this  sentence :  ''  Radium- 
clocks  have  been  made  that  will  go  for  a  million  years ;  but  I 
believe  that  the  Universe  was  never  made  and  will  go  on  for 
ever."  This,  of  course,  is  vague,  because,  if  the  term  "'  uni- 
verse ''  is  taken  to  mean  "  the  all  that  exists,"  or  rather,  ''  all 
that  exists,  that  ever  has  existed,  or  that  ever  will  exist,''  it  is 
a  truism,  because  that  includes  all  life  and  God.  But  "  uni- 
verse "  is  taken  bv  llaeckel  and  his  school  to  mean  the  ma- 
terial  universe,  and  to  definitely  exclude  spirit  and  god. 

A  great  modern  physicist.  Professor  Svanto  Arrhenius,  in 
the  preface  to  his  recent  work.  Worlds  in  the  ^Making,  con- 
cludes thus: 

"My  guiding  principles  in  this  exposition  of  cosinogonic  pi-(.h- 
lems  has  been  the  conviction  that  the  Universe  in  its  csseiico  luis 
always  been  what  it  is  now.  Matter,  energy,  and  life  iiavo  only 
varied  as  to  shape  and  position  in  space." 

This  will  be  taken  to  mean,  and  T  presume  does  mean, 
"matter"  and  "life"  as  we  know  them  on  the  earth,  and  to 
exclude,  as  Haeckol  does  drfinitely,  spirit  and  deity.  The 
general  conception  of  all  these  writers  seems  to  be,  that  it  is 


380  THE  WORLD  OF  LIFE 

easier,  simpler,  more  scientific,  to  assume  that  '^  matter, 
energy,  and  life "  as  we  see  them,  have  existed,  the  same  in 
essence  though  in  ever  varying  forms,  from  all  eternity,  and 
will  continue  to  exist  to  all  eternity,  than  to  assume  any  intel- 
ligent power  beyond  what  we  see. 

Xow  the  idea,  that  positing  eternity  for  matter  and  for  or- 
ganised life,  and  for  all  the  forces  of  nature,  overcomes  diffi- 
culties or  renders  their  existence  at  the  stage  they  have  now 
reached  at  all  intelligible,  is,  I  maintain,  the  very  opposite  of 
the  truth,  and  arises  from  a  want  of  real  thought  as  to  what 
"  eternity "  means.  Take,  first,  "  life "  culminating  in 
"  man."  It  is  admitted  that  there  has  been  a  continuous 
though  not  uniform  progress  from  the  first  organic  cell  up  to 
man.  To  arrive  at  that  end  it  has  admittedly  occupied  a  very 
large  portion  of  the  duration  of  the  habitability  of  the  planet, 
and  of  the  sun  as  a  heat  and  life-giver.  It  is  also  assumed 
that,  to  ensure  the  persistence  of  life  w^hen  suns  cool  and  planets 
are  unsuitable,  either  the  germs  of  life  must  be  carried  through 
space  (at  the  zero  of  temperature)  from  one  solar  system  to 
another  till  they  chance  to  alight  upon  one  where  the  condi- 
tions of  life  are  suitable,  or  they  must  have  developed  again 
out  of  dead  matter.  All  this  is  overwhelmingly  difficult, —  but 
let  us  grant  it  all.  Let  us  grant  also  that  there  are  forces  and 
energies  capable  of  automatically  building  up  progressively 
developing  forms  of  sentient  life,  such  as  have  been  built  up 
on  the  earth.  Then,  if  these  forces  and  energies  have  acted 
from  all  eternity,  they  must  have  resulted  in  an  infinite  life- 
development,  that  is,  in  beings  inconceivably  higher  than  we 
are.  Now  we,  who,  as  they  all  tell  us,  are  poor  miserable 
creatures  of  a  day,  have  yet  got  to  know  much  of  the  universe, 
to  apply  its  forces,  and  thus  to  modify  nature  —  so,  an  eternity 
of  progress  at  the  same  rate  (and  as  there  is  progress  there  is 
no  cause  why  it  should  stop)  must  necessarily  have  produced  an 
infinite  result  —  that  is,  beings  which  as  compared  with  us 
Avould  be  gods.     And   as  you   cannot   diminish   eternity,   then 


MYSTERY  OF  THE  CELL  381 

long  ages  before  the  first  rudiment  of  life  appeared  npon  the 
earth,  long  before  all  the  suns  we  see  had  l>eeonie  suns,  the  in- 
finite development  had  been  at  work  and  must  liavc  ])r(>diic(Ml 
gods  of  infinite  degrees  of  powei-,  any  one  of  whom  would  pre- 
sumably be  quite  capable  of  starting  such  a  solar  system  as 
ours,  or  one  immensely  larger  and  better,  and  of  so  determin- 
ing the  material  constitution  of  an  "  earth  "  as  to  initiate  and 
guide  a  course  of  development  which  would  have  resulted  in 
a  far  higher  being  than  man.  Once  assume  a  mind-developing 
power  from  all  eternity,  and  it  must,  noiu,  and  at  all  earlier 
periods  of  the  past  have  resulted  in  beings  of  infinite  power  — 
what  we  should  term  —  Gods  ! 

It  may,  I  think,  be  stated  generally,  that  whatever  has  an 
inherent  power  of  increase  or  decrease,  of  growth,  develop- 
ment, or  evolution,  cannot  possibly  have  existed  from  a  past 
"  eternity ''  unless  the  law  of  its  evolution  is  an  ever-recurrent 
identical  cycle,  in  which  case,  of  course,  it  may,  conceivably, 
have  existed  from  eternity  and  continue  through  an  eternity  of 
future  cycles,  all  identical;  and,  therefore,  such  cycles  could 
never  produce  anything  that  had  not  been  produced  an  in- 
finite number  of  times  before.  Is  this  a  satisfactory  outcome 
for  an  eternal  self-existent  universe  ?  Is  this  easier,  simpler, 
more  rational,  more  scientific,  more  philosophical,  than  to 
posit  one  supreme  mind  as  self-existent  and  eternal,  of  which 
our  universe  and  all  universes  are  the  manifestations  I  And 
yet  the  "  infinity  and  eternity  "  men  call  themselves  ^'  monists,'^ 
and  claim  to  be  the  only  logical  and  scientific  thinkers.  With 
them  matter,  ether,  life  —  (surely  three  absolutely  distinct 
things) — with  all  the  wonderful  laws,  and  forces,  and  direc- 
tive agencies  which  they  imply,  and  without  which  none  of 
them  could  for  a  moment  exist,  all  are  to  be  accounted  for  and 
explained  by  the  one  illogical  assumption,  their  eternity ;  the 
one  complete  misnomer,  monism ;  the  one  alleged  fundamental 
law  which  explains  nothing,  the  "  law  of  substance." 

It  will  be  seen  that  this  alleged  explanation  —  the  eternal 
material    universe  —  does   not    touch    the    necessitv,    becominc: 


382  THE  WORLD  OF  LIFE 

more  clear  every  day,  not  for  blind  laws  and  forces,  but  for 
immanent  directive  and  organising  mind,  acting  on  and  in 
every  living  cell  of  every  living  organism,  during  every  moment 
of  its  existence.  I  think  1  have  sufficient! v  shown  that  with- 
ont  this,  life,  as  we  know  it,  is  altogether  unthinkable.  Xo 
^^  eternal  "  existence  of  matter  will  make  this  in  the  remotest 
defifree  imaginable.  It  is  this  difficultv  which  the  ^^  monists  '' 
and  the  "  eternalists  "  of  the  Llaeckel  and  Verworu  type  abso- 
lutely shirk,  putting  us  off  ^vith  the  wildest  and  most  contra- 
dictory assertions  as  to  what  they  have  proved ! 

I  venture  to  hope  and  to  believe  that  such  of  my  readers 
as  have  accompanied  me  so  far  through  the  present  volume, 
and  have  had  their  memory  refreshed  as  to  the  countless 
marvels  of  the  world  of  life ;  culminating  in  the  two  great 
mysteries  —  that  of  the  human  intellect  wdth  all  its  powers 
and  capacities  as  its  outcome,  that  of  the  organic  cell  with 
all  its  complexity  of  structure  and  of  hidden  powers  as  its 
earliest  traceable  origin  —  will  not  accept  the  loud  assertion, 
that  everything  exists  because  it  is  eternal  as  a  sufficient  or  a 
convincing  explanation.  A  critical  examination  of  the  sub- 
ject demonstrates,  as  the  greatest  metaphysicians  agree,  that 
everything  but  the  Absolute  and  Unconditioned  must  have  had 
a  beginning. 


CHAPTER  XVIII 

THE    ELEMENTS   AND   WATER,    IN   RELATION    TO    THE   LIFE-WORLD 

I  HAVE  already  (in  Chapter  XVI.)  given  the  statements  of 
two  continental  physiologists  as  to  great  chemical  complexity 
of  the  proteid  molecule,  involving  as  it  does,  in  certain  cases 
already  studied,  a  combination  of  about  two  thousand  chemical 
atoms.  A  more  recent  authority  (Mr.  W.  Bate  Hardy)  is  of 
opinion  that  this  molecule  really  contains  about  thirty  thou- 
sand atoms,  while  the  most  complex  molecule  known  to  the 
organic  chemist  is  said  to  contain  less  than  a  hundred.  One 
of  the  results  of  this  extreme  complexity  is  that  almost  all  the 
products  of  the  vegetable  and  animal  kingdoms  are  what  are 
termed  hydro-carbons,  that  is,  they  consist  of  compounds  of 
carbon,  with  hydrogen,  oxygen,  or  nitrogen,  or  any  or  all  of 
them,  combined  in  an  almost  infinite  variety  of  ways.  Yet 
the  compounds  of  these  four  elements  already  known  are  more 
numerous  than  those  produced  by  all  the  other  elements,  more 
than  seventy  in  number. 

This  abundance  is  largely  due  to  the  fact  that  the  very  same 
combination  of  carbon  with  the  three  gaseous  constituents  of 
the  carbon-compounds  often  produces  several  substances  very 
different  in  appearance  and  properties.  Thus  dextrine  (or 
British  gum),  starch,  and  cellulose  (the  constituents  of  the 
fibres  of  plants)  all  consist  of  six  atoms  of  carbon,  ton  of 
hydrogen,  and  five  of  oxygen ;  yet  they  have  very  different 
properties,  cellulose  being  insoluble  in  water,  alcohol,  or  ether ; 
dextrine  soluble  in  water  but  not  in  alcohol ;  while  starch  is  only 
soluble  in  Avarm  water.  These  differences  are  supposed  to  be 
due  to  the  different  arrangement  of  the  atoms,  and  to  their  being 
combined  and  recombinod  in  dift'orent  ways;  and  as  the  more 
atoms  are  used,  the  possible  complexity  of  these  arrangements 

383 


384  THE  WORLD  OF  LIFE 

becomes  greater,  and  the  vast  numbers  and  marvellous  diversity 
of  the  organic  compounds  becomes  to  some  extent  intelligible. 
Professor  Kerner,  referring  to  the  three  substances  just  men- 
tioned, gives  the  following  suggestive  illustration  of  their 
diverse  properties,  of  which  I  have  only  mentioned  a  few.  He 
says : 

"  If  six  black,  ten  blue,  and  five  red  balls  are  placed  close  to- 
gether in  a  frame,  they  can  be  grouped  in  the  most  diverse  ways 
into  beautiful  symmetrical  figures.  They  are  always  the  same 
balls,  they  always  take  up  the  same  space,  and  yet  the  effect  of  the 
figures  produced  by  the  different  arrangements  is  wholly  distinct. 
It  may  be  imagined,  similarly,  that  the  appearance  of  the  whole 
mass  of  a  carbon-compound  becomes  different  in  consequence  of 
the  arrangement  of  the  atoms,  and  that  not  only  the  appearance 
but  even  the  physical  properties  undergo  striking  alterations." 

Another  and  perhaps  more  interesting  example,  illustrated 
by  a  diagram,  is  given  by  Mr.  W.  Bate  Hardy  in  his  lecture 
already  referred  to.     He  says : 

"  Here  is  a  simple  and  startling  case.  The  molecules  of  two 
chemical  substances,  benzonitrile  and  phenylisocyanide,  are  com- 
posed of  seven  atoms  of  carbon,  five  of  hydrogen,  and  one  of 
nitrogen : 

N  C 

H— C  I        1  C— H  H— C  I         I  C— H 

H— C  I         I  C— H  H— C  I         I  C— H 

c  c 

Benzonitrile.  Phenylisocyanide. 

The  only  difference  in  the  arrangement  of  the  atoms  is  that  those 
of  nitrogen  and  carbon  are  reversed.  But  the  properties  of  these 
two  substances  are  as  unlike  as  possible.  The  first  is  a  harmless 
fluid  with  an  aromatic  smell  of  bitter  almonds.  The  second  is 
very  poisonous,  and  its  odour  most  offensive." 


THE  ELEMENTS  AXl)  LIFE  385 

Here  only  three  elements  are  combined,  and  in  identical  pro- 
portions. We  can  imagine,  therefore,  what  endless  diversities 
arise  when  to  these  are  added  anv  of  nine  other  elements,  and 
these  in  varying  proportions,  as  Avell  as  being  groii])ed  in  every 
possible  manner. 

The  fact  of  ^^  isomerism,"  or  of  different  substances,  often 
with  very  different  properties,  having  the  very  same  chemical 
composition,  is  now  so  familiar  to  chemists  as  to  excite  com- 
paratively little  attention,  yet  it  is  really  a  marvel  and  a  mys- 
tery almost  equal  to  that  of  the  organic  cell  itself.  It  is 
probably  dependent  upon  the  highly  complex  nature  of  the 
molecules  of  the  elements,  and  also  of  the  atoms  of  which  these 
molecules  are  built  up;  while  atoms  themselves  are  now  be- 
lieved to  be  complex  systems  of  electrons,  which  are  held  to  be 
the  units  of  electricity  and  of  matter.  It  is  these  electrons 
and  their  mysterious  forces  that  give  to  matter  all  its  mechan- 
ical, physical,  and  chemical  properties,  including  those  which, 
in  the  highly  complex  protoplasm,  have  rendered  possible  that 
whole  world  of  life  we  have  been  considering  in  the  present 
volume. 

Here,  then,  we  find,  as  before,  that  the  further  back  we  go 
towards  the  innermost  nature  of  matter,  of  life,  or  of  mind, 
we  meet  with  new  complications,  new  forces,  new  agencies,  all 
pointing  in  one  direction  towards  the  final  outcome  —  the  buikl- 
ing  up  of  a  living  sentient  form,  which  should  be  the  means 
of  development  of  the  enduring  spirit  of  man. 

Important  and  Unimportant  Elements 

If  we  look  at  the  long  list  of  between  seventy  and  eighty 
elements  now  known  we  shall  see  that  a  comparatively  suuill 
number  of  these  (less  than  one-fourth)  seem  to  play  any  im- 
portant part  either  in  the  structure  of  the  earth  as  a  phinet, 
or  in  the  constitution  of  the  organised  l)eings  that  have  been 
developed  upon  it.  The  most  important  of  the  elements  is 
oxygen,  which  is  not  only  an  essential  in  the  structure  of  all 
living  things,  but  forms  a  large  part  of  the  air  and  the  water 


386  THE  WORLD  OF  LIFE 

which  are  essential  to  their  contiiiTied  existence.  It  is  also  a 
constituent  of  almost  every  mineral  and  rock,  and  is  estimated 
to  form  about  47  per  cent  of  the  whole  mass  of  the  globe.  The 
next  most  abundant  elements  are  silicon,  aluminium,  and  iron, 
which  form  25,  8,  and  7  per  cent  respectively  of  the  earth- 
mass.  Then  follow  calcium,  magnesium,  sodium,  and  potas- 
sium, contributing  from  about  4  to  2  per  cent  of  the  whole; 
while  no  other  element  forms  so  much  as  one  per  cent,  and  the 
majority  probably  not  more  than  one-fiftieth  or  one-hundredth 
of  one  per  cent. 

The  gases,  hydrogen  and  nitrogen,  are,  however,  exceedingly 
important  as  forming  with  oxygen  the  atmosphere  and  the 
oceans  of  the  globe,  which  by  their  purely  physical  action  on 
climate,  and  in  causing  perpetual  changes  on  the  earth's  sur- 
face, have  rendered  the  development  of  the  organic  w^orld  pos- 
sible. These  ten  elements  appear  to  be  all  that  were  necessary 
to  constitute  the  earth  as  a  planet,  and  to  bring  about  its  varied 
surface  of  mountain  and  valley,  rivers  and  seas,  volcanoes  and 
glaciers ;  but  in  order  to  develop  life,  and  thus  clothe  the  earth 
with  ever-growing  richness  of  vegetation  and  ever-changing 
forms  of  animals  to  be  sustained  by  that  vegetation,  four  other 
elements  were  required  —  carbon,  sulphur,  phosphorus,  and 
chlorine  —  but  these  being  either  gaseous  or  of  very  small  spe- 
cific gravity,  and  thus  existing  (perhaps  exclusively)  near  the 
earth's  surface,  comparatively  little  of  them  was  needed. 


Elements  in  Protoplasm  in  Order  of  their 
Abundance    {approximately). 


1. 

Hydrogen 

2. 

Carl)  011 

3. 

Oxvgen 

4. 

Nitrogen 

5. 

Sulphur 

6. 

Iron 

Phosphorus 

8. 

Chlorine 

9. 

Sodium 

10. 

Potassium 

11. 

Calcium 

12. 

Magnesium 

List  of  the  More  Important  Elements 

Elements  in   the  Earth  in   Order  of  their 
Quantity    {approximately). 

per  cent. 

1.  Oxygen    47 

2.  Silicon 25 

3.  Aluminium   8 

4.  Iron     7 

5.  Calcium     4 

6.  Magnesium  3 

7.  Sodium    2.5 

8.  Potassium     2.5 

9.  Hydrogen    (?)  0.1 

10.  Nitrogen    (?)  0.1 

All  others (?)    0.8 


100 


THE  ELEME:N^TS  AXD  life  387 

The  two  elements  in  italics  —  iiilicoit  and  Alumijiiuni — altlioiii:li  form- 
ing  a  large  proportion  of  the  earth's  substance,  are  not  ctmcndal  constitu- 
ents of  protophism,  although  occasionally  forming  part  of  it. 

In  the  list  of  the  more  important  elements  here  given,  I 
have  arranged  them  in  two  series,  the  first  showing  the  essential 
constituents  of  protoplasm ;  the  second  showing  the  ten  which 
are  the  most  important  constituents  of  the  earth's  mass  as 
known  to  geologists  and  physicists.  The  four  which  are  itali- 
cised in  the  first  list  do  not  appear  in  the  second,  and  cannot, 
therefore,  be  considered  as  forming  an  essential  portion  of  the 
rock-structure  of  the  earth,  although  without  them  it  seems 
fairly  certain  that  the  life-world  could  not  have  existed. 

The  Elements  in  relation  to  Man 

So  far  as  we  can  see,  therefore,  the  fourteen  elements  in 
these  two  lists  would  have  sufficed  to  brine:  about  all  the  essen- 
tial  features  of  our  earth  as  w^e  now  find  it.  All  the  others 
(more  than  sixty)  seem  to  be  surplusage,  many  exceedingly 
rare,  and  none  forming  more  than  a  minute  fraction  of  the 
mass  of  the  earth  or  its  atmosphere.  All  except  seven  of  these 
are  metals,  including  (with  iron)  the  seven  metals  known  to 
the  ancients  and  even  to  some  prehistoric  races.  The  seven 
ancient  metals  are  gold,  silver,  copper,  iron,  tin,  lead,  and  mer- 
cury. All  of  these  are  widely  distributed  in  the  rocks.  They 
are  most  of  them  found  occasionally  in  a  pure  state,  and  are 
also  obtained  from  their  ores  without  much  difficulty,  which 
has  led  to  their  being  utilised  from  very  early  times.  But 
though  these  metals  (except  iron)  appear  to  serve  no  important 
purpose  either  in  the  earth  itself  or  in  tlie  vegetable  or  animal 
kingdoms,  they  have  yet  been  of  very  gTcat  importance  in  the 
history  of  man  and  the  development  of  civilisation.  From  very 
remote  times  gold  and  silver  have  been  prized  for  their  extreme 
beauty  and  comparative  rarity;  the  search  after  them  has  led 
to  the  intercourse  between  various  races  and  peoples,  and  to 
the  establishment  of  a  world-wide  conmierce ;  wliile  the  facility 
W'ith  wdiich  they  could  be  worked  and  polished  called  fortli  the 


388  THE  WORLD  OF  LIFE 

highest  powers  of  the  artist  and  craftsman  in  the  making  of 
ornaments,  coins,  drinking-vessels,  etc.,  many  of  which  have 
come  down  to  ns  from  early  times,  sometimes  showing  a  beauty 
of  design  which  has  never  been  surpassed.  Our  own  earliest 
rudiments  of  civilisation  were  probably  acquired  from  the 
Phoenicians,  who  regularly  came  to  Cornwall  and  our  southern 
coasts  to  purchase  tin. 

Each  of  the  seven  metals  (and  a  few  others  now  in  com- 
mon use)  has  very  special  qualities  which  renders  it  useful  for 
certain  purposes,  and  these  have  so  entered  into  our  daily  life 
that  it  is  difficult  to  conceive  how  we  should  do  without  them. 
Without  iron  and  copper  an  effective  steam-engine  could  not 
have  been  constructed,  our  whole  vast  system  of  machinery 
could  never  have  come  into  existence,  and  a  totallv  distinct 
form  of  civilisation  would  have  developed  —  perhaps  more  on 
the  lines  of  that  of  China  and  Japan.  Is  it,  we  may  ask,  a 
pure  accident  that  these  metals,  with  their  special  physical 
qualities  which  render  them  so  useful  to  us,  should  have  ex- 
isted on  the  earth  for  so  many  millions  of  years  for  no  appar- 
ent or  possible  use ;  but  becoming  so  supremely  useful  when 
Man  appeared  and  began  to  rise  tow^ards  civilisation  ? 

But  an  even  more  striking  case  is  that  of  the  substances 
which  in  certain  combinations  produce  glass.  Sir  Henry  Ros- 
coe  states  that  silicates  of  the  alkali  metals,  sodium  and  potas- 
sium, are  soluble  in  water  and  are  non-crystalline ;  those  of 
the  alkaline  earths,  calcium,  etc.,  are  soluble  in  acid  and  are 
crystalline;  but  by  combining  these  silicates  of  sodium  and 
calcium,  or  of  potassium  and  calcium,  the  result  is  a  substance 
which  is  noi  soluble  either  in  water  or  acids,  and  which,  when 
fused  forms  glass,  a  perfectly  transparent  solid,  not  crystallised 
but  easily  cut  and  ]3olished,  elastic  within  limits,  and  when 
softened  by  heat  capable  of  being  moulded  or  twisted  into  an 
endless  variety  of  forms.  It  can  also  be  coloured  in  an  infinite 
variety  of  tints,  while  hardly  diminishing  its  transparency. 

The  value  of  cheap  glass  for  windows  in  cold  or  changeable 
climates  cannot  be  over-estimated.     Without  its  use  in  bottles, 


THE  ELEMENTS  AXD  LIEE  389 

tubes,  etc.,  chemistry  could  hardly  exist ;  while  astronomy  could 
not  have  advanced  beyond  the  stage  to  which  it  had  Itecn 
brought  by  Copernicus,  Tycho  Brahe,  and  Kepler.  It  rfu- 
dered  possible  the  microscope,  the  telescope,  and  the  si)ectro- 
scope,  three  instruments  without  which  neither  the  starry  heav- 
ens nor  the  myriads  of  life-forms  would  have  had  their  inner 
mysteries  laid  open  to  us. 

One  more  example  of  a  recent  discovery  of  one  of  the  rarest 
substances  in  nature  —  radium  —  and  its  extraordinarv  effects, 
points  in  the  same  direction.  So  far  as  known  at  present,  this 
substance  may  or  may  not  be  in  any  way  important  either 
to  the  earth  as  a  planet  or  for  the  development  of  life  upon 
it ;  but  the  most  obvious  result  of  its  discovery  seems  to  bo 
the  new  light  it  throws  on  the  nature  of  matter,  on  the  con- 
stitution of  the  atom,  and  perhaps  also  on  the  mysterious  ether. 
It  has  come  at  the  close  of  a  century  of  wonderful  advance 
in  our  knowledge  of  matter  and  the  mysteries  of  the  atom. 
Many  other  rare  elements  or  their  compounds  are  now  being 
found  to  be  useful  to  man  in  the  arts,  in  medicine,  or  by  the 
light  they  throw  on  chemical,  electrical,  or  ethereal  forces.^ 

If  now  we  take  the  occurrence  of  all  these  apparently  use- 
less substances  in  the  earth's  crust ;  the  existence  in  tolerable 
abundance,  or  very  widely  spread,  of  the  seven  metals  known 
to  man  during  his  early  advances  towards  civilisation,  and  the 
many  ways  in  which  they  helped  to  further  that  civilisation ; 
and,  lastly,  the  existence  of  a  few  elements  which,  when  spe- 
cially combined,  produce  a  substance  without  which  modern 
science  in  almost  all  its  branches  would  have  been  impossible, 
w^e  are  broui2:ht  face  to  face  with  a  body  of  facts  which  are 
wholly  unintelligible  on  any  other  theory  than  that  the  earth 
(and  the  universe  of  which  it  form>  a  part)   was  constituted 

1  While  this  chapter  is  being  written  I  see  it  announced  that  two  of  the 
rarest  of  the  elements,  lanthanium  and  noodyniuin.  have  l)ei'n  found  to  pro- 
vide (through  some  of  their  comjiounds)  light-lilters,  which  increase  the 
efficiency  of  the  spectroscope  in  <1h»  study  of  the  planetary  atmospheres, 
and  may  thus  be  the  menus  of  still  furthoi-  extending  oiu*  knowledge  of  the 
universe. 


390  THE  WOKLD  OF  LIFE 

as  it  is  in  order  to  supply  us,  when  the  proper  time  came,  with  * 
the  means  of  exploring  and  studying  the  inner  mechanism 
of  the  world  in  which  we  live  —  of  enabling  us  to  appreciate 
its  overwhelming  complexity,  and  thus  to  form  a  more  ade- 
quate conception  of  its  author,  and  of  its  ultimate  cause  and 
purpose. 

I  have  already  shown  that  the  postulate  of  a  past  eternal 
existence  is  no  explanation,  and  leads  to  insuperable  difficulties. 
A  beginning  in  time  for  all  finite  things  is  thus  demonstrable  ^ 
but  a  beginning  implies  an  antecedent  cause,  and  it  is  impos- 
sible to  conceive  of  that  cause  as  other  than  an  all-pervading 
mind. 

The  Mystery  of  Carbon:  the  Basis  of  Organised  Matter  and 

of  Life 

It  is  universally  admitted  that  carbon  is  the  one  element 
which  is  essential  to  all  terrestrial  life.  It  will  be  interesting, 
therefore,  to  give  a  brief  statement  of  what  is  known  about 
this  very  important  substance.  Although  it  is  so  familiar  to 
us  in  its  solid  form  as  charcoal,  or  in  a  more  mineralised  form 
as  black-lead  or  graphite,  it  is  doubtful  whether  it  exists  un- 
combined  on  the  earth  except  as  a  product  of  vegetation. 
Though  graphite  (plumbago)  is  found  in  some  of  the  earliest 
rocks,  yet  it  is  believed  that  some  forms  of  vegetation  existed 
much  earlier.  Graphite  has  also  occurred  (rarely)  in  mete- 
orites, but  I  am  informed  by  my  friend.  Professor  Meldola, 
that  it  cannot  be  decided  whether  this  is  derived  from  carbon- 
dioxide  gas  or  from  gaseous  carbon.  Sir  William  Huggins 
was  also  doubtful  as  to  the  state  in  Avhich  it  exists  in  the  sun 
and  comets,  w^hether  as  carbon-vapour  or  a  hydrocarbon.  But 
the  most  interesting  point  for  us  is  that  it  exists  as  a  constitu- 
ent of  our  atmosphere,  of  which  carbon-dioxide  fonns  about 
^■g^ooth  part,  equal  to  about  yoVo't^^  ^2iYi  by  weight  of  solid 
carbon ;  and  it  is  from  this  that  the  whole  of  the  vegetable 
kingdom  is  built  up.  The  leaves  of  plants  contain  a  green 
substance  named  chlorophyll,  which  by  the  aid  of  sunlight  can 


THE  ELEMENTS  AND  JJFE  391 

extract  the  carbon  from  the  gas,  and  there  is  no  other  means 
known  hj  which  this  can  be  done  at  ordinary  temperatures. 
The  chemist  has  to  use  the  electric  spark,  or  very  high  tem- 
peratures, to  perform  what  is  done  by  the  green  leaves  at  the 
ordinary  temperatures  in  which  we  live. 

The  reverse  operation  of  combining  carbon  with  other  ele- 
ments is  equally  difficult.  In  Chambers's  Encyclopaedia  we 
find  the  following  statement:  '^  At  ordinary  temperatures  all 
the  varieties  of  carbon  are  extremely  unalterable ;  so  much  so 
that  it  is  customary  to  burn  the  ends  of  piles  of  wood  whirh 
are  to  be  driven  into  the  ground,  so  that  the  coating  of  non- 
decaying  carbon  may  preserve  the  inner  wood.  Wood-charcoal, 
however,  burns  very  easily,  animal  charcoal  less  so ;  then  fol- 
low in  order  of  difficulty  of  combustion  coke,  anthracite,  black- 
lead,  and  the  diamond."  The  two  latter  withstand  all  tem- 
peratures, except  the  very  highest  obtainable.  These  various 
states  of  carbon  differ  in  other  respects.  Ordinary  carbon  is 
a  good  conductor  of  electricity;  the  diamond  is  a  non-con- 
ductor. 

Carbon  unites  chemically  with  almost  all  the  other  elements, 
either  directly  or  by  the  interv^ention  of  some  of  the  gases.  It 
also  possesses,  as  Sir  Henry  Roscoe  says :  "  A  fundaiTiental  and 
distinctive  quality.  This  consists  in  the  power  which  this  ele- 
ment possesses,  in  a  much  higher  degree  than  any  of  the  others, 
of  uniting  with  itself  to  form  complicated  compounds,  contain- 
ing an  aggregation  of  carbon-atoms  united  with  either  oxygen, 
hydrogen,  nitrogen,  or  several  of  these,  bound  together  to  form 
a  distinct  chemical  Avhole.'' 

Carbon  is  also  the  one  element  that  is  never  absent  from 
any  part  or  product  of  the  vegetable  or  animal  kingdoms ;  and 
its  more  special  property  is  that,  when  combined  with  hydro- 
gen, nitrogen,  and  oxygen,  together  with  a  small  quantity 
(about  1  per  cent)  of  sulphur,  it  forms  the  whole  group  <if 
substances  called  albuminoids  (of  which  white  of  egg  is  the 
type),  and  which,  much  diluted,  forms  the  essential  part  of 
the  blood,  from  which   all  the  solids  and  fluids  of  organisms 


392  THE  WORLD  OF  LIFE 

are  secreted.  It  was  on  these  special  features  of  carbon  that 
Haeckel  founded  his  celebrated  carbon-theory  of  life,  which 
he  has  thus  stated :  '^  The  peculiar  chemico-physical  properties 
of  carbon  —  especially  the  fluidity  and  the  facility  of  decom- 
position of  the  most  elaborate  albuminoid  compounds  of  car- 
bon —  are  the  sole  and  the  mechanical  causes  of  the  specific 
phenomena  of  movement,  which  distinguish  organic  from  in- 
organic substances,  and  which  are  called  life,  in  the  usual  sense 
of  the  word.''  And  he  adds :  "  Although  this  '  carbon-theory  ' 
is  warmly  disputed  in  some  quarters,  no  better  monistic  theory 
has  yet  appeared  to  replace  it." 

What  a  wonderfully  easy  way  of  explaining  a  mystery! 
Carbon  forms  a  constituent  of  the  bodies  and  of  the  products 
of  all  living  things ;  therefore  carbon  is  the  cause  of  life  and  all 
its  phenomena ! 

But  besides  the  carbon  in  the  atmosphere  an  immense  quan- 
tity exists  in  the  various  limestone  rocks,  consisting  of  car- 
bonate of  lime  (CaCOg).  It  is  quite  possible,  however,  that 
these  are  all  results  of  animal  secretions  as  in  coral-reefs;  or 
of  the  debris  of  the  hard  parts  of  marine  animals,  as  in  the 
Globigerina-ooze.  Limestones  exist  among  the  oldest  rocks, 
but  as  we  know  that  marine  life  was  very  much  older,  this  is 
no  objection.  All  water  holds  in  solution  a  large  quantity  of 
carbonic  acid  gas,  so  that  both  air  and  water  are  the  source 
of  the  most  essential  elements  for  building  up  the  bodies  of 
plants  and  animals. 

The  ocean  also  holds  a  large  amount  of  carbonate  of  lime 
in  solution,  and  this  is  kept  permanently  dissolved  by  the  large 
amount  of  carbonic  acid  gas  always  present,  which  is  sufficient 
to  dissolve  five  times  the  amount  of  carbonate  of  lime  which 
actually  exists.  Deposits  of  inorganic  limestone  are,  there- 
fore, now  never  formed  except  by  long-continued  evaporation 
in  isolated  bodies  of  salt  water.  This  renders  it  more  probable 
that  all  pure  limestone  rocks  are  really  very  ancient  coral-reefs 
consolidated  and  crystallised  by  heat  and  pressure  under  masses 
of  superincumbent  strata. 


THE  ELEMENTS  AMJ  EIFE  ;]U0 

The  altogether  remarkable  and  exceptional  properties  of 
carbon  are  fully  reeognised  by  modern  chemists,  as  well  shown 
by  Professor  II.  E.  Armstrong's  statements  in  his  Presidential 
Address  to  the  British  Association  in  lUU'J : 

"The  central  luminary  of  our  system,  let  me  insist,  is  the  ele- 
ment carbon.  The  constancy  of  this  element,  the  firmness  of  its 
affections  and  affinities,  distinguishes  it  from  all  others.  It  is  only 
when  its  attributes  are  understood  that  it  is  possible  to  frame  any 
proper  picture  of  the  possibilities  which  lie  before  us  of  the  place  of 
our  science  in  the  cosmos." 

And  a  little  further  on  he  says: 

"  Our  present  conception  is,  that  the  carbon  atom  has  tetrahodral 
properties  in  the  sense  that  it  has  four  affinities  which  operate 
practically  in  the  direction  of  four  radii  proceeding  from  the  centre 
towards  the  four  solid  angles  of  a  regular  tetrahedron.  .  .  . 
The  completeness  with  which  the  fundamental  properties  of  the 
carbon  atom  are  symbolised  by  a  regular  tetrahedron  being  alto- 
gether astounding." 


And  again : 

"  It  would  seem  that  carbon  has  properties  which  are  altogether 
special;  the  influence  which  it  exerts  upon  other  elements  in  de- 
priving them  of  their  activity  is  so  remarkable." 

We  see,  therefore,  that  carbon  is  perhaps  the  most  unique, 
in  its  physical  and  chemical  properties,  of  the  whole  series  of 
the  elements,  and  so  far  as  the  evidence  points,  it  seems  to 
exist  for  the  one  purpose  of  rendering  the  development  of 
organised  life  a  possibility.  It  further  appears  that  its  unique 
chemical  properties,  in  combination  with  those  of  the  other 
elements  which  constitute  protoplasm,  have  enabled  the  various 
forms  of  life  to  produce  that  almost  infinite  variety  of  sub- 
stances adapted  for  man's  use  and  enjoyment,  and  especially 
to  serve  the  purposes  of  his  ever-advancing  research  into  the 
secrets  of  the  universe. 


3yi  THE  WOELD  OF  LIFE 

Water:  its  relations  to  Life  and  to  Man 

The  compound  water  is  as  essential  for  building  up  living 
organisms  as  is  carbon,  and  it  exhibits  peculiarities  almost 
as  striking  as  those  of  that  element.  Its  more  obvious  quali- 
ties are  singularly  unlike  those  of  its  components,  oxjgen  and 
hydrogen :  oxygen  supports  combustion,  water  checks  or  destroys 
it;  hydrogen  burns  readily,  water  is  incombustible.  Water  is 
wonderfully  stable  at  ordinary  temperatures,  hence  it  is  the 
most  innocuous  of  fluids ;  it  is  also  an  almost  universal  solvent, 
hence  its  great  value  in  cookery,  in  the  arts,  and  for  cleansing 
purposes.  Besides  being  absolutely  essential  for  vegetable  and 
animal  life  it  has  qualities  which  render  it  serviceable  to  civil- 
ised man,  both  in  his  pleasures  and  his  scientific  discoveries. 
Absolutely  pure  water  is  a  non-conductor  of  electricity;  but  as 
all  natural  waters  contain  gases  or  salts  in  solution,  it  then  be- 
comes a  conductor,  and  is  partly  decomposed,  or  becomes  an 
electrolyte.  The  various  curious  facts  connected  with  water 
are  so  puzzling,  that  in  April  1910  the  Faraday  Society  held 
a  general  discussion  in  order  to  arrive  at  some  solution  of  what 
is  termed  in  the  Electrical  Review  "  the  most  complex  of  prob- 
lems." One  of  the  facts  that  seem  to  be  now  generally 
accepted  is,  that  water  is  not  the  simple  compound,  H2O,  it 
is  usually  held  to  be,  but  is  really  a  compound  of  three  hydrols, 
II2O  being  gaseous  water,  (H20)3  being  ice,  while  liquid  water 
is  a  mixture  of  these  or  (H20)2. 

Professor  H.  E.  Armstrong  put  forward  this  view  in  1908, 
and  in  the  Address  already  quoted  he  says: 

"  Although  it  is  generally  admitted  that  water  is  not  a  uniform 
substance  but  a  mixture  of  units  of  different  degrees  of  molecular 
complexity,  the  degree  of  complexity  and  the  variety  of  forms  is' 
probably  under-estimated,  and  little  or  no  attention  has  been  paid 
to  the  extent  to  which  alterations  produced  by  dissolving  substances 
in  it  may  be  the  outcome  and  expression  of  changes  in  the  water 
itself." 


THE  ELEMENTS  AXD  LIFE  31)5 

And  again : 

As  water  is  altogether  peculiar  in  its  activity  as  a  solvent,  and 
is  a  solvent  which  gives  rise  to  conducting  solutions,  an  explanation 
of  its  efficiency  must  be  souglit  in  its  own  special  and  peculiar 
properties." 

Here  again  we  find  that  the  most  common  and  familiar  of 
the  objects  around  us,  and  wdiich  we  are  accustomed  t<t  l<M.k 
upon  as  the  most  simple,  may  yet  really  be  full  of  marvel  and 
mystery. 

The  strange  chemical  properties  of  water  are  probably  the 
cause  of  the  singular  but  most  important  fact  that  water  reaches 
its  greatest  density  at  4°C.  (=  about  7°  F.)  above  the  freez- 
ing-point. If  this  curious  anomaly  did  not  exist  the  coldest 
w^ater  would  ahvays  be  at  the  bottom,  and  would  freeze  there; 
and  thus  many  lakes  and  rivers  during  a  hard  winter  would 
become  solid  ice,  w-hich  the  succeeding  summer  might  not  bo 
able  to  melt.     Sir  Henry  Koscoe  says: 

"  If  it  were  not  for  this  apparently  unimportant  property  our 
climate  would  be  perfectly  Arctic,  and  Europe  would  in  all  proba- 
bility be  as  uninhabitable  as  Melville  Island."  ^ 

The  very  remarkable  and  highly  complex  relations  between 
the  quantity  of  water  in  our  oceans,  seas,  and  lakes,  and  the 
earth's  habitability^  have  been  fully  discussed  in  chapters  xii. 
and  xiii.  of  my  volume  on  Man's  Place  in  the  Tni verse.  1 
will  only  mention  here,  that  in  those  chapters  I  liave  pointed 
out  the  probable  origin  of  the  great  oceanic  basins;  the  pro<ifs 
of  their  permanence  throughout  all  geological  tinu^;  the  prob- 
able causes  of  that  pennanence;  the  necessity  of  such  perma- 
nence to  preserve  the  continuity  of  life-dcvel<ipment.  not  only 
on  the  earth  as  a  whole,  but  on  each  of  the  izvont  continents; 
and,  lastly,  how^  all  these  phenomena  have  cond)ined  to  secure 
that  general  uniformity  of  climatic  conditions  throughout  the 
whole  period  of  the  existence  of  terrestrial  life  which  was  essen- 

1  Elementary  Chemistry,  p.  38. 


396  THE  WORLD  OF  LIFE 

tial  to  its  full  and  continuous  development.  There  is,  I  be- 
lieve, no  more  curious  and  important  series  of  phenomena  con- 
nected with  the  possibilities  of  life  upon  the  earth  than  those 
described  in  the  chapters  above  referred  to. 

Water  as  Preparing  the  Earth  for  Man 

There  remain  vet  some  further  relations  of  water  to  life 
which  may  be  here  briefly  noticed.  Among  the  various  agen- 
cies that  have  modelled  and  remodelled  the  earth's  surface, 
water  has  played  the  most  important  part.  It  is  to  water  that 
we  owe  its  infinite  variety,  its  grandeur,  its  picturesqueness,  its 
adaptability  to  a  highly  varied  vegetable  and  animal  life;  and 
this  v/ork  has  been  carried  out  through  its  manifold  physical 
and  chemical  properties.  It  is  in  its  three  states,  solid,  liquid, 
and  gaseous,  that  water  exerts  its  most  continuous  and  effective 
powers;  and  it  is  enabled  to  do  this  because,  though  each  of 
these  has  its  own  limited  range  of  temperature,  they  yet  over- 
lap, as  it  w^ere,  and  can  therefore  act  in  unison.  Thus  within 
the  narrow  limits  of  temperature  adapted  to  organic  life  we 
have  both  ice  and  water-vapour  as  well  as  liquid  water,  in 
almost  continuous  action.  Through  dew,  mist,  and  rain,  water 
penetrates  every  fissure  of  the  rocks ;  through  the  carbonic  acid 
gas  dissolved  in  it,  the  rocks  are  slowly  decomposed ;  by  the 
expansion  of  water  between  39°  and  32°  F.  it  freezes  in  the 
upper  parts  of  the  fissures,  and  when  the  temperature  continues 
to  fall  the  further  expansion  during  ice-crystallisation  forces 
the  rocks  asunder.  The  most  massive  rocks  at  high  altitudes 
are  first  cracked  and  fissured  by  expansion  and  contraction  due 
to  alternations  of  temperature  caused  by  sun-heat,  then  decom- 
posed by  rain,  then  fractured  by  the  irresistible  force  of  ice- 
formation.  On  a  large  scale  in  polar  regions,  and  everywhere 
at  great  altitudes,  snowfields  and  permanent  glaciers  are 
formed,  which  not  only  carry  down  enormous  quantities  of 
debris  on  their  surfaces  or  embedded  in  their  substance,  but 
with  the  help  of  that  which  is  carried  along  the  valley-floors 
they  rest  on,  and  by  the  enormous  weight  of  the  ice  itself  often 


THE  ELEMENTS  ASD  LIFE  :]07 

miles  in  thickness,  grind  out  deep  valleys  and  lake-l)n,sins  be- 
fore cosmic  or  other  agencies  cause  them  to  melt  away. 

This  continuous  water-action  goes  on  perpetually  in  every 
continent,  and  is  the  great  agent  in  producing  that  inlinite 
variety  of  contour  of  the  land  surface  —  level  plains,  gentle 
slopes,  beautifully  rounded  downs,  wave-like  undulations,  val- 
leys in  every  possible  variety,  basin-shaped,  trough-shaped, 
bounded  by  smooth  slopes  or  rugged  precipices,  straight  or 
winding,  and  often  leading  us  up  into  the  very  heart  of  grand 
mountain  scenery,  with  their  domes  and  ridges  and  rocky  peaks, 
their  swift-flowing  streams,  rushing  torrents,  dark  ravines,  and 
glorious  cascades,  in  endless  variety,  beauty,  and  grandeur. 

And  all  this  we  owe  to  what  are  termed  the  "'  properties 
of  water,"  that  extremely  simple  and  unappreciated  element, 
which  still  abounds  in  mysteries  that  puzzle  the  men  of  science. 
Without  water  in  all  its  various  forms  and  with  its  many  useful 
but  very  familiar  properties,  not  only  would  life  on  the  earth 
be  impossible,  but  unless  it  had  existed  in  the  vast  profusion 
of  our  ocean  depths,  and  been  endowed  with  its  less  familiar 
powers  and  forces,  the  whole  world,  instead  of  being  a  con- 
stantly varvinff  scene  of  beauty  —  a  verv"  e:arden  of  delights 
for  the  delectation  of  all  the  higher  faculties  of  man, —  would 
have  been  for  the  most  part  a  scene  of  horror,  perhaps  the 
sport  of  volcanic  agencies  of  disruption  and  upheaval  only 
modified  by  the  disintegrating  effects  of  sun   and  wind-action. 

Our  earth  mi2:ht  thus  have  been  in  a  state  not  verv  dissimilar 
from  that  in  which  the  moon  appears  to  be ;  not  perhajis  with- 
out a  considerable  amount  of  life,  but  with  little  of  its  variety, 
and  with  hardly  any  of  that  exquisite  charm  of  contour  and  veg- 
etation which  we  are  now  only  beginning  to  appreciate  and 
to  enjoy. 


CHAPTEK   XIX 

IS   NATURE    CRUEL  ?       THE    PURPOSE    AND    LIMITATIONS    OF    PAIN 

A  VERY  large  number  of  persons  of  many  shades  of  opinion 
and  various  degrees  of  knowledge  are  disturbed  by  the  con- 
templation of  the  vast  destruction  of  life  ever  going  on  in  the 
world.  This  disturbance  has  become  greater,  has  become  a 
mystery,  almost  a  nightmare  of  horror,  since  organic  evolution 
through  the  survival  of  the  fittest  has  been  accepted  as  a  law 
of  nature.  The  working  out  of  the  details  of  the  Darwinian 
theory  has  forced  public  attention  to  this  destruction,  to  its 
universality,  to  its  vast  amount,  to  its  being  the  essential  means 
of  progress,  to  its  very  necessity  as  affording  the  materials  for 
that  constant  adaptation  to  changes  in  the  environment  which 
has  been  essential  for  the  development  of  the  whole  organic 
world. 

The  knowledge  of  this  startling  fact  has  come  to  us  at  a 
time  W'hen  there  is  a  great  deal  of  humanity  in  the  world,  when 
to  vast  numbers  of  persons  every  kind  of  cruelty  is  abhorrent, 
bloodshed  of  every  kind  is  repugnant,  and  deliberate  killing 
of  a  fellow-man  the  greatest  of  all  crimes.  The  idea,  there- 
fore, that  the  whole  system  of  nature  from  the  remotest  eons 
of  the  past  —  from  the  very  first  appearance  of  life  upon  the 
earth  —  has  been  founded  upon  destruction  of  life,  on  the  daily 
and  hourly  slaughter  of  myriads  of  innocent  and  often  beau- 
tiful living  things,  in  order  to  support  the  lives  of  other  crea- 
tures, which  others  are  specially  adapted  to  destroy  them,  and 
are  endowed  w^ith  all  kinds  of  w^eapons  in  order  that  they  may 
the  more  certainly  capture  and  devour  their  victims, —  all  this 
is  so  utterly  abhorrent  to  us  that  w-e  cannot  reconcile  it  with 
an  author  of  the  universe  who  is  at  once  all-wise,  all-powerful, 
and  all-good.     The  consideration  of  these  facts  has  been  a  mys- 

398 


IS  XATURE  CKUEL?  399 

tery  to  the  religious,  and  has  undoubtedly  aided  in  the  produc- 
tion of  that  widesj^read  pessimism  which  exists  to-day;  whiK- 
it  has  confirmed  the  materialist,  and  great  numbers  of  students 
of  science,  in  the  rejection  of  any  supreme  intelligence  as  hav- 
ing created  or  designed  a  universe  which,  iK'ing  founded  on 
cruelty  and  destruction,  they  believe  to  be  innnoral. 

I  am  not  aware  that  Darwin  dealt  with  this  question  at  all, 
except  in  the  concluding  words  of  his  Origin  of  Species,  where 
he  says: 

"  Thus,  from  the  war  of  nature,  from  famine  and  death,  the 
most  exalted  object  we  are  capable  of  conceiving,  namely,  the  pro- 
duction of  the  higher  animals,  directly  follows." 

This  admits  the  facts  as  generally  conceived;  and,  without 
palliating  them,  sets  on  the  other  side  the  great  compensating 
result. 

Much  more  to  the  point  is  the  concluding  sentence  of  his 
chapter  on  the  Struggle  for  Existence : 

"  When  we  reflect  on  this  struggle,  we  may  console  ourselves 
with  the  full  belief,  that  the  war  of  nature  is  not  incessant,  that  no 
fear  is  felt,  that  death  is  generally  prompt,  and  that  the  vigorous, 
the  health}^,  and  the  happy  survive  and  multiply." 

These  statements  are,  I  believe,  strictly  true,  but  they  do  not 
comprise  all  that  can  be  said  on  the  question.  Before  dealing 
w^ith  the  whole  subject  from  the  standpoint  of  evolution,  1  will 
quote  the  opinions  of  tw^o  eminent  biologists,  as  showing  how 
the  matter  has  impressed  even  thoughtful  and  instructed 
writers.  Professor  J.  Arthur  Thomson  (of  Aberdeen  Tni- 
versity),  wdien  reviewing  my  Darwinism  in  The  Theological 
Eeview,  said: 

"Tone  it  down  as  you  will,  the  fact  remains  that  "Darwinism 
regards  animals  as  going  upstairs,  in  a  strugirle  for  individual  ends, 
often  on  tlie  corpses  of  their  fellows,  often  Ity  a  hlood-and-iron  com- 
petitinn,  often  by  a  strange  mixture  of  blood  and  cunning,  in  which 
eacli  looks  out  for  liimsolf  and  extinction  besots  the  hindmost.     We 


400  THE  WORLD  OF  LIFE 

are  not  interested  in  any  philosophical  justification  of  this  natural 
or  unnatural  method  until  we  are  sure  that  it  is  a  fact." 

These  words  do  not,  I  hope,  represent  the  Professor's  view 
to-day ;  and  I  believe  I  shall  be  able  to  show  that  they  by  no 
means  give  an  accurate  impression  of  what  the  facts  really 
are.  About  the  same  period  the  late  Professor  Huxley  used 
terms  still  more  erroneous  and  misleading.  He  spoke  of  the 
myriads  of  generations  of  herbivorous  animals  which  ''  have 
been  tormented  and  devotired  by  carnivores  " ;  of  the  carnivores 
and  herbivores  alike  as  being  "  subject  to  all  the  miseries  inci- 
dental to  old  age,  disease,  and  over-multiplication " ;  and  of 
the  "  more  or  less  enduring  suffering ''  which  is  "  the  meed  of 
both  vanquished  and  victor  " ;  and  he  concludes  that,  since  thou- 
sands of  times  a  minute,  were  our  ears  shai'p  enough,  we  should 
hear  sighs  and  groans  of  pain  like  those  heard  by  Dante  at 
the  gate  of  Hell,  the  world  cannot  be  governed  by  w^hat  we 
call  benevolence.-^  Such  a  strong  opinion,  from  such  an  author- 
ity, must  have  influenced  thousands  of  readers ;  but  I  shall  be 
able  to  show  that  these  statements  are  not  supported  by  facts, 
and  that  they  are,  moreover,  not  in  accordance  wdth  the  prin- 
ciples of  that  Darwinian  evolution  of  which  Huxley  was  so 
able  and  staunch  a  defender. 

It  is  the  influence  of  such  statements  as  these,  repeated  and 
even  exaggerated  in  newspaper  articles  and  reviews  all  over 
the  country,  that  has  led  so  many  persons  to  fall  back  upon  the 
teaching  of  Haeckel  —  that  the  universe  had  no  designer  or 
creator,  but  has  always  existed ;  and  that  the  life-pageant,  with 
all  its  pain  and  horror,  has  been  repeated  cycle  after  cycle  from 
eternity  in  the  past,  and  will  be  repeated  in  similar  cycles  for 
ever.  We  have  here  presented  to  us  one  of  the  strangest 
phenomena  of  the  human  mind  —  that  numbers  of  intelligent 
men  are  more  attracted  by  a  belief  which  makes  the  amount 
of  pain  which  they  think  does  exist  on  the  earth  last  for  all 
eternity  in  successive  worlds  without  any  permanent  and  good 

iThe  Nineteenth    Century,  February   1888,  pp.    162-163. 


IS  NATURE  CRUEL?  401 

result  whatever,  than  by  another  belief,  wliich  admits  the  suiiio 
amount  of  pain  into  one  earth  only,  and  for  a  limitod  period, 
while  whatever  pain  there  is  only  exists  for  the  grand  ])iirpose 
of  developing  a  race  of  spiritual  beings,  who  may  thereafter 
live  without  physical  pain  —  also  for  all  eternity  I  Tu  put  it 
shortly  —  they  prefer  the  conception  of  a  universe  in  which 
pain  exists  perpetually  and  uselessly,  to  one  in  whieli  the  pain 
is  strictly  limited,  while  its  beneficial  results  are  eternal! 

Xone  of  these  writers,  however,  nor,  so  far  as  T  know,  anv 
evolutionist,  has  ever  gone  to  the  root  of  the  problem,  by  con- 
sidering the  very  existence  of  pain  as  being  one  of  the  essential 
factors  in  evolution;  as  having  been  developed  in  the  animal 
world  for  a  purpose ;  as  being  strictly  subordinated  to  the  law 
of  utility ;  and  therefore  never  developed  beyond  what  was 
strictly  needed  for  the  preservation  of  life.  It  is  from  this 
point  of  view  that  I  shall  now  discuss  the  question,  and  it  will 
be  found  that  it  leads  us  to  some  very  important  conclusions. 
In  order  to  do  this,  we  must  consider  what  were  the  conditions 
of  the  problem  when  life  first  appeared  upon  the  earth. 

The  general  facts  as  to  the  rate  of  increase  of  animals  and 
plants  have  been  given  in  Chapter  VII.  of  this  work ;  but  even 
these  facts,  remarkable  as  they  are,  seem  altogether  insignifi- 
cant when  compared  with  those  of  the  lowest  fonns  of  life. 
The  most  startling  calculation  of  the  kind  I  have  seen  was  given 
last  year  in  a  Royal  Institution  lecture  on  The  Physical  Basis 
of  Life,  by  W.  B.  Hardy,  F.R.S.  (a  Cambridge  tutor),  as  to 
one  of  the  infusoria  (Paramecium)  much  used  for  experiment 
and  observation  on  account  of  its  comparatively  large  size 
(about  T^ijth  inch  long)  and  its  being  veiw  easily  procured. 
This  species  multiplies  by  division  about  twice  in  three  days,  and 
has  been  kept  under  observation  thus  multiplying  for  more 
than  100  generations.  ]N'ow  it  is  not  very  difiieult  to  calcnlato 
what  quantity  of  Paramecia  would  be  produced  in  any  given 
number  of  generations,  and  what  space  they  would  occupy. 
Xo  non-mathematical  person  can  imagine  or  will  Wieve  the 
result.     It   is,   that   if   the   conditions   were   such    (ns    regards 


40^  THE  WORLD  OF  LIFE 

space,  food,  etc.)  that  the  Paramecivim  could  go  on  increasing 
for  350  generations,  that  is  to  say,  for  about  two  years,  the 
produce  would  he  sufficient  in  bulk  to  occupy  a  sphere  larger 
than  the  known  universe! 

I^ow  taking  this  as  a  type  of  the  Protozoa  —  the  one-celled 
animals  and  plants  that  still  exist  in  thousands  of  varied  forms 
—  we  see  in  imagination  the  beginnings  of  the  vast  world  of 
life ;  and  we  also  see  the  absolute  necessity  —  if  it  was  to  con- 
tinue and  develop  as  it  has  done,  filling  the  earth  with  infinite 
variety,  and  beauty,  and  the  joy  of  life  —  for  higher  and 
higher  forms  to  come  successively  into  being,  and  for  these 
forms  to  exist  upon  the  food  provided  by  the  bodies  of  the 
lower.  It  follows  that  almost  simultaneously  with  the  first 
plant-cells  which  had  the  power  of  extracting  carbon  from  the 
carbonic  acid  gas  in  the  air  and  water  and  converting  it  into 
protoplasm,  the  first  animal  cells  must  also  have  arisen;  and 
both  must  very  rapidly  have  diverged  into  varied  forms  in 
order  to  avoid  the  whole  of  the  water  from  being  monopolised 
by  some  one  form  of  each,  and  thus  checking,  if  not  altogether 
preventing,  the  development  of  higher  and  more  varied  forms. 
Variation  and  selection  were  thus  necessary  from  the  very  first 
— ^  were  even  far  more  necessary  than  at  any  later  period,  in 
order  to  avoid  the  possibility  of  the  whole  available  space  being 
occupied  by  some  very  low  form  to  the  exclusion  of  all  others. 
Some  writers  have  thought  that,  owing  to  the  very  uniform 
conditions  in  the  primeval  ocean,  the  development  of  new  forms 
of  life  would  then  proceed  more  slowly  than  now.  But  a  con- 
sideration of  the  enormously  rapid  increase  of  primitive  life 
leads  to  the  conclusion  that  the  reverse  was  the  case.  It  seems 
more  probable  that  evolution  proceeded  as  much  more  rapidly 
than  now,  as  the  rate  of  increase  of  the  lower  animals  is  more 
rapid  than  that  of  the  highest  animals.  This  view  is  supported 
by  the  fact,  observed  long  ago  in  the  Foraminifera,  that  their 
variability  was  immensely  greater  than  in  any  other  animals ; 
and  this  will  serve  to  shorten  the  time  required  for  the  develop- 


IS  NATURE  CRUEL?  403 

ment  of  the  life  of  the  Cambrian  period  from  the  earliest  one- 
celled  animals. 

We  find,  then,  that  the  whole  syj^tcm  of  lifc-chn'elopmcnt  is 
that  of  the  lower  providing  food  for  th(^  hi^lur  in  ever-expand- 
ing circles  of  organic  existence.  That  system  has  succeeded 
marvelh)usly,  even  gloriously,  inasmuch  as  it  has  produced,  as 
its  final  outcome,  Max,  the  one  being  who  can  ai)preciate  the 
infinite  variety  and  beauty  of  the  life-world,  the  one  being  who 
can  utilise  in  any  adequate  manner  the  myriad  products  of  its 
mechanics  and  its  chemistry.  Now,  whatever  view  we  may 
take  of  the  universe  of  matter,  of  life,  and  of  mind,  this  suc- 
cessful outcome  is  a  proof  that  it  is  the  only  i)racticable  metlnjd, 
the  only  method  that  could  succeed.  Uor  if  we  assume  (with 
the  monists)  that  it  has  been  throughout  the  outcome  of  the 
blind  forces  of  nature  —  of  '^  the  rush  of  atoms  and  the  clash 
of  w^orlds  " —  then,  as  they  themselves  admit,  being  the  out- 
come of  a  past  eternity  of  trial  and  error,  it  could  not  have 
been  otherwise.  If,  on  the  other  hand,  it  is,  as  1  urge,  the 
foreordained  method  of  a  supreme  mind,  then  it  must  with 
equal  certainty  be  the  hest,  and  almost  certainly  the  onJn 
method,  that  could  have  subsisted  through  the  immeasurable 
ages  and  could  have  then  produced  a  being  capable,  in  some 
degree,  of  comprehending  and  appreciating  it.  For  that  is 
surely  the  glory  and  distinction  of  man  —  that  he  is  continually 
and  steadily  advancing  in  the  Txnowledge  of  the  vastness  and 
mvstery  of  the  universe  in  which  he  lives:  and  how  anv  stu- 
dent  of  any  part  of  that  universe  can  declare,  as  so  numy  do, 
that  there  is  only  a  difference  of  degree  between  himself  and 
the  rest  of  the  animal-world, —  that,  in  Tlaeckel's  forcible 
words,  '"  Our  own  human  nature  sinks  to  the  level  of  a  ]dacental 
mammal,  which  has  no  more  value  for  tlie  universe  at  large 
than  the  ant,  the  fly  of  a  summer's  day,  the  microscopic  infu- 
sorium, or  the  smallest  baeillu>^." —  i<  altoo;other  beyond  mv 
comprehension.^ 

1  See  The  Riddle  of  the  Universe,  chap.  xiii.    (p.  87,  col.   1). 


404  THE  WORLD  OF  LIFE 

The  Evolution  of  Pain 

Taking  it  then  as  certain  that  the  whole  world-process  is  as 
it  is,  because  it  is  the  only  method  that  could  have  succeeded, 
or  that  if  there  were  alternative  methods  this  was  the  best,  let 
us  ascertain  what  cojiclusions  necessarily  follow  from  it.  And, 
first,  we  see  that  the  whole  cosmic  process  is  based  upon  funda- 
mental existences,  properties,  and  forces,  the  visible  results  of 
which  we  term  the  ''  laws  of  nature,''  and  that,  in  the  organic 
world  at  all  events,  these  laws  bring  about  continuous  develop- 
ment, on  the  whole  progressive.  One  of  the  subsidiary  results 
of  this  mode  of  development  is,  that  no  organ,  no  sensation,  no 
faculty  arises  before  it  is  needed,  or  in  a  greater  degree  than 
it  is  needed.  This  is  the  essence  of  Darwinism.  Hence  we 
may  be  sure  that  all  the  earlier  forms  of  life  possessed  the 
minimum  of  sensation  required  for  the  purposes  of  their  short 
existence ;  that  anything  approaching  to  what  we  term  ''  pain  " 
was  imknown  to  them.  Thev  had  certain  functions  to  fulfil 
which  they  carried  out  almost  automatically,  though  there  was 
no  doubt  a  difference  of  sensation  just  enough  to  cause  them  to 
act  in  one  way  rather  than  another.  And  as  the  whole  purpose 
of  their  existence  and  rapid  increase  was  that  they  should  pro- 
vide food  for  other  somewhat  higher  forms  —  in  fact,  to  be 
eaten  —  there  was  no  reason  whatever  whv  that  kind  of  death 
should  have  been  painful  to  them.  They  could  not  avoid  it, 
and  were  not  intended  to  avoid  it.  It  may  even  have  been  not 
only  absolutely  painless  but  slightly  pleasurable  —  a  sensation 
of  warmth,  a  quiet  loss  of  the  little  consciousness  they  had, 
and  nothing  more  — "  a  sleep  and  a  forgetting." 

People  will  not  keep  always  in  mind  that  pain  exists  in  the 
world  for  a  purpose,  and  a  most  beneficent  purpose  —  that  of 
aiding  in  the  preservation  of  a  sufficiency  of  the  higher  and 
more  perfectly  organised  forms,  till  they  have  reproduced  their 
hind.  This  being  the  case,  it  is  almost  as  certain  as  anything 
not  personally  known  can  be,  that  all  animals  which  breed  very 
rapidly,  which  exist  in  vast  numbers,  and  which  are  necessarily 


IS  NATURE  CRUEL?  405 

kept  down  to  their  average  population  by  the  agency  of  those 
that  feed  upon  them,  have  little  sensitiveness,  perhaps  only  a 
slight  discomfort  under  the  most  severe  injuries,  and  that  they 
probably  suffer  nothing  at  all  when  being  devoured.  For  why 
should  they  ?  They  exist  to  be  dt.'voured ;  their  enormous  pow- 
ers of  increase  are  for  this  end;  they  are  subject  to  no  danger- 
ous bodily  injury  until  the  time  comes  to  be  devoured,  and 
therefore  they  need  no  guarding  against  it  through  the  agency 
of  pain.  In  this  category,  of  painless,  or  almost  painless  ani- 
mals, I  think  we  may  place  almost  all  aquatic  animals  up  to 
fishes,  all  the  vast  hordes  of  insects,  probably  all  IMollusca  and 
worms;  thus  reducing  the  sphere  of  pain  to  a  minimum 
throughout  all  the  earlier  geological  ages,  and  very  largely  even 
now. 

When  we  see  the  sharp  rows  of  teeth   in  the  earlier  binU 
and  flying  reptiles,  we  immediately  think  of  the  pain  suffered 
by  their  prey ;  but  the  teeth  were  in  all  probability  necessary 
for   seizing  the    smooth-scaled   fishes   or   smaller   land-reptiles, 
which  were  swallowed  a  moment  afterw^ards ;  and  as  no  useful 
purpose  would  be  served  by  the  devoured  suffering  pain  in  the 
process,  there  is  no  reason  to  believe  that  they  did  so  suffer. 
The  same  reasoning  will  apply  to  most  of  the  smaller  birds 
and  mammals.     These  are  all  so  wonderfullv  adjusted  to  their 
environments,  that,  in  a  state  of  nature,  they  can  hardly  suffer 
at  all  from   what   we  teinn   accidents.     Birds,   mice,  squiiTcls, 
and  the  like,  do  not  get  limbs  broken  by  falls,  as  we  do.     They 
leani  so  quickly  and  certainly  not  to  go  beyond  their  powers 
in  climbing,  jumping,  or  flying,  that  they  are  probahly  never 
injured  except  by  rare  natural  causes,  such  a^^  lightning,  hail, 
forest-fires,  etc.,  or  by  fichtino-  amono'  themselves;   and   those 
who  are  injured   without  being  killed  by  thc-^e  various  causes 
form  such  a  minute  fraction  of  the  whole  as  to  be  reasonably 
negligible.     The  wounds  received  in  fighting  seem  to  be  rarely 
serious,   and   the  rapiditv  with   whidi   <uch   wonn<ls   h(>al    in   a 
state  of  nature  shows  that   whatever  pain  exists  is  not  long- 
continued. 


406  THE  WOKLD  OF  LIFE 

It  is  only  the  large,  heavy,  slow-moving  mammals  which  can 
be  subject  to  much  accidental  injury  in  a  state  of  nature  from 
such  causes  as  rock-falls,  avalanches,  volcanic  eruptions,  or 
falling  trees ;  and  in  these  cases  by  far  the  larger  portion  would 
either  escape  unhurt  or  would  be  killed  outright,  so  that  the 
amount  of  pain  suffered  would,  in  any  circumstances,  be  small ; 
and  as  pain  has  been  developed  for  the  necessary  purpose  of 
safe-guarding  the  body  from  often-recurring  dangers,  not  from 
those  of  rare  occurrence,  it  need  not  be  very  acute.  Perhaps 
self-mutilation,  or  fighting  to  the  death,  are  the  greatest  dan- 
gers which  most  wild  animals  have  to  be  guarded  against ;  and 
no  very  extreme  amount  of  pain  would  be  needed  for  this  pur- 
pose, and  therefore  w^ould  not  have  been  produced. 

But  it  is  undoubtedly  not  these  lesser  evils  that  have  led  to 
the  outcry  against  the  cruelty  of  nature,  but  almost  wholly 
what  is  held  to  be  the  widespread  existence  of  elaborate  con- 
trivances for  shedding  blood  or  causing  j^ain  that  are  seen 
throughout  nature  —  the  vicious-looking  teeth  and  claws  of  the 
cat-tribe,  the  hooked  beak  and  prehensile  talons  of  birds  of 
prey,  the  poison  fangs  of  serpents,  the  stings  of  wasps,  and 
many  others.  The  idea  that  all  these  w^eapons  exist  for  the 
purpose  of  shedding  blood  or  giving  pain  is  wholly  illusory. 
As  a  matter  of  fact,  their  effect  is  whollv  beneficent  even  to 
the  sufferers,  inasmuch  as  they  tend  to  the  diminution  of  pain. 
Their  actual  purpose  is  always  to  prevent  the  escape  of  cap- 
tured food  —  of  a  w^ounded  animal,  which  would  then,  indeed, 
suffer  useless  pain,  since  it  would  certainly  very  soon  be  cap- 
tured again  and  be  devoured.  The  canine  teeth  and  retractile 
claws  hold  the  prey  securely ;  the  serpent's  fangs  paralyse  it ; 
and  the  w^asp's  sting  benumbs  the  living  food  stored  up  for  its 
young,  or  serves  as  a  protection  against  being  devoured  itself 
by  insect-eating  birds ;  which  latter,  probably,  only  feel  enough 
pain  to  warn  them  against  such  food  in  future.  The  evidence 
that  animals  which  are  devoured  by  lion  or  puma,  by  wolf  or 
wdld  cat,  suffer  very  little,  is,  I  think,  conclusive.  The  sud- 
denness and  violence  of  the  seizure,  the  blow  of  the  paw,  the 


IS  XATUKE  CiWELi  407 

simultaneous  deep  wounds  by  teeth  and  claws,  either  cause 
death  at  once,  or  so  paralyse  the  nervous  system  that  no  pain 
is  felt  till  death  very  rapidly  follows.  It  must  be  remembered 
that  in  a  state  of  nature  the  Carnivora  hunt  and  kill  to  satisfy 
hunger,  not  for  amusement;  and  all  conclusions  derived  from 
the  house-fed  cat  and  mouse  are  fallacious.  Even  in  the  case 
of  man,  with  his  highly  sensitive  nervous  system,  which  has 
been  developed  on  account  of  his  unprotected  skin  and  excessive 
liability  to  accidental  injury,  seizure  by  a  lion  or  tiger  is  hardly 
painful  or  mentally  distressing,  as  testified  by  those  who  have 
been  thus  seized  and  have  escaped.^ 

Our  whole  tendency  to  transfer  our  sensations  of  pain  to  all 
other  animals  is  grossly  misleading.  The  probability  is,  that 
there  is  as  great  a  gap  between  man  and  the  lower  animals  in 
sensitiveness  to  pain  as  there  is  in  their  intellectual  and  moral 
faculties;  and  as  a  concomitant  of  those  higher  faculties.  We 
require  to  be  more  sensitive  to  pain  because  of  our  bare  skin 
with  no  protective  armour  or  thick  pads  of  hair  to  ward  off 
blows,  or  to  guard  against  scratches  and  wounds  from  the  many 
spiny  or  prickly  plants  that  abound  in  every  part  of  the  world ; 
and  especially  on  account  of  our  long  infancy  and  childhood. 
And  here  I  think  I  see  the  solution  of  a  problem  which  has 
long  puzzled  me  —  wJiy  man  lost  his  hairy  covering,  especially 
from  his  back,  where  it  would  be  so  useful  in  carrying  off 
rain.  He  inaij  have  lost  it,  gradually,  from  the  time  when  he 
first  became  Man  —  the  spiritual  being,  the  'Miving  soul"  in 
a  corporeal  body,  in  order  to  render  him  7nore  se7isitivc.  From 
that  moment  he  was  destined  to  the  intellectual  advance  which 
we  term  civilisation.  He  was  to  be  exposed  to  a  thousand  self- 
created  dangers  totally  unknown  to  the  rest  of  the  animal  world. 
His  very  earliest  advance  towards  civilisation  —  the  use  of  fire 
—  became  thenceforth  a  daily  and  liourlv  danger  to  him,  to  be 
guarded  against  only  by  sudden  and  acute  pain ;  and  as  he 
advanced  onwards  and  his  life  became  more  complex;  as  he 
surrounded    himself   with    dwellings,    and    made    clothing    and 

1  See  a  brief  discussion  «>f  tliis  snl»jc<'t   in   my   Darwinism,   i>]>.   :^()-40. 


408  THE  WOKLD  OF  LIFE 

adopted  cookery  as  a  daily  practice,  he  became  more  and  more 
exposed  to  loss,  to  injury,  and  to  death  from  fire,  and  thus 
would  be  subject  to  the  law  of  selection  by  which  those  less 
sensitive  to  fire,  and  therefore  more  careless  in  the  use  of  it, 
became  eliminated. 

Ilia  tools  continually  becoming  more  and  more  dangerous, 
and  his  weapons  becoming  more  and  more  destructive,  w^ere 
alike  a  danger  to  him.  The  scythe  and  the  sickle  caused  acci- 
dental woimds,  as  did  the  needle  and  the  knife.  The  club  and 
the  axe,  the  spear  and  the  arrow,  the  sword  and  the  dagger, 
caused  wounds  which,  if  not  avoided,  led  quickly  to  death. 
Hence  beneficent  pain  increased  with  him  as  a  warning  of  dan- 
ger, impelling  him  to  the  avoidance  of  wounds  by  skill  and 
dexterity,  by  the  use  of  padded  clothing  or  of  flexible  armour; 
w^hile  nature's  remedies  were  sought  out  to  heal  the  less  deadly 
injuries,  and  thus  avoid  long  suffering  or  permanent  disable- 
ment. And  ever  as  civilisation  went  on,  such  dangers  in- 
creased. Explosives  caused  a  new  kind  of  wound  from  musket 
or  pistol,  and  later  from  bombs  and  mines.  Boats  and  ships 
were  built  and  the  ocean  traversed.  Endless  forms  of  machin- 
ery were  invented,  at  first  hand-worked,  and  not  dangerous  to 
the  worker,  but  soon  driven  by  steam  with  such  force  that  if 
carelessly  entangled  in  it  the  worker's  limbs  might  be  torn  from 
his  body.  And  all  this  went  on  increasing  till  at  last  a  large 
proportion  of  the  human  race  laboured  daily  in  peril  of  life 
or  limb,  or  of  painful  wounds,  or  worse  diseases.  Against  this 
vast  ever-present  network  of  dangers,  together  with  the  ever- 
present  danger  of  consuming  fire,  man  is  warned  and  protected 
by  an  ever-increasing  sensibility  to  pain,  a  horror  at  the  very 
sight  of  wounds  and  blood ;  and  it  is  this  specially  developed  sen- 
sibility that  we,  most  illogically,  transfer  to  the  animal-world 
in  our  wholly  exaggerated  and  often  quite  mistaken  views  as  to 
the  crueltv  of  nature! 

As  a  proof  of  the  increased  sensibility  of  the  civilised  as 
compared  with  the  more  savage  races,  we  have  the  well-known 


IS  NATURE  CRUEL  ^  409 

facts  of  the  natives  of  many  parts  of  the  world  enduring  what 
to  us  would  be  dreadful  torments  without  exhibiting  any  signs 
of  pain.  Examples  of  this  are  to  be  found  in  almost  every 
book  of  travels.  I  will  here  only  mention  one.  Among  most 
of  the  Australian  tribes  there  is  a  regular  scale  of  punishment 
for  various  offences.  When  a  man  entices  awav  another  man's 
wife  (or  in  some  other  offence  of  an  allied  nature)  the  allotted 
punishment  is,  that  the  complainant  and  his  nearest  relatives, 
often  eight  or  ten  in  number  or  even  more,  are  to  be  allowed 
to  thrust  a  spear  of  a  certain  size  into  the  offender's  leg  between 
ankle  and  knee.  The  criminal  appears  before  the  chiefs  of  the 
tribe,  he  holds  out  his  leg,  and  one  after  another  the  members 
of  the  offended  family  walk  up  in  turn,  each  sticks  in  his 
spear,  draws  it  out,  and  retires.  When  all  have  done  so,  the 
leg  is  a  mass  of  torn  flesh  and  skin  and  blood ;  the  sufferer  has 
stood  still  without  shrinking  during  the  whole  operation.  Tie 
then  goes  to  his  hut  with  his  wife,  lies  down,  and  she  covers 
the  leg  with  dust  —  probably  fine  wood  ashes.  For  a  few 
days  he  is  fed  with  a  thin  gruel  only,  then  gets  up,  and  is  very 
soon  as  well  as  ever,  except  for  a  badly  scarred  leg.  Of  course 
we  cannot  tell  what  he  actually  suffered,  but  certainly  the  aver- 
age European  could  not  have  endured  such  pain  unmoved. 

This,  however,  is  only  an  illustration.  It  is  not  essential 
to  the  argument,  which  is  founded  wholly  on  the  principles 
of  Darwinian  evolution.  One  of  these  principles,  much  in- 
sisted on  by  Darwin,  is,  that  no  organ,  faculty,  or  sensation 
can  have  arisen  in  animals  except  through  its  utility  to  the 
species.  The  sensation  of  pain  has  been  thus  developed,  and 
must  therefore  be  proportionate  in  each  species  to  its  needs, 
not  heyond  those  needs.  In  the  lowest  animals,  whose  numbers 
are  enormous,  whose  powers  of  increase  are  excessive,  whose 
individual  lives  are  measured  bv  hours  or  davs,  and  which 
exist  to  be  devoured,  pain  would  bo  almost  or  quite  useless,  and 
would  therefore  not  exist.  Only  as  the  organism  increased  in 
complexity,  in  duratiou  of  life,  nnrl  in  exposure  to  danger  which 


no  THE  WORLD  OF  LIFE 

migtit  possibly  lead  to  its  death  before  it  could  either  leave 
offspring  or  serve  as  food  to  some  higher  form  —  only  then 
could  pain  have  any  use  or  meaning. 

I  have  now  endeavoured,  very  roughly,  to  follow  out  this 
principle  to  its  logical  results,  which  are,  that  only  in  the  higher 
and  larger  members  of  the  highest  vertebrates  —  mammals  and 
birds,  do  the  conditions  exist  which  render  acute  sensations  of 
pain  necessary,  or  even  serviceable.  Only  in  the  most  highly 
organised,  such  as  dogs  and  horses,  cattle,  antelopes,  and  deer, 
does  there  appear  to  be  any  need  for  acute  sensations  of  pain, 
and  these  are  almost  certainly,  for  reasons  already  given,  very 
much  less  than  ours.  The  logical  conclusion  is,  therefore,  that 
they  only  suffer  a  very  moderate  amount  of  pain  from  such 
bodily  injuries  as  they  are  subject  to  in  a  state  of  nature. 

I  have  already  shown  that  in  most  cases,  even  from  our  much 
higher  standard,  their  death  would  be  rapid  and  almost  pain- 
less ;  whence  it  follows,  that  the  widespread  idea  of  the  cruelty 
of  nature  is  almost  wholly  imaginary.  It  rests  on  the  false 
assumption  that  the  sensations  of  the  lower  animals  are  neces- 
sarily equal  to  our  own,  and  takes  no  account  whatever  of  these 
fundamental  principles  of  evolution  which  almost  all  the  critics 
profess  to  accept. 

There  is,  of  course,  a  large  body  of  facts  which  indicate  that 
whole  classes  of  animals,  though  very  highly  organised,  suffer 
nothing  which  can  be  called  pain,  as  in  the  insects ;  and  similar 
facts  show  us  that  even  the  highest  warm-blooded  animals  suffer 
very  much  less  than  we  do.  But  my  argument  here  does  not 
depend  upon  any  such  evidence,  but  on  the  universally  accepted 
doctrine  of  evolution  through  adaptation.  According  to  that 
theory,  it  is  only  life-preserving  variations,  qualities,  or  faculties 
that  have  survival  value:  pain  is  one  of  the  most  important  of 
these  for  us,  but  it  is  by  no  means  so  important  to  any  other 
animal,  ^o  other  animal  needs  the  pain-sensations  that  we 
need;  it  is  therefore  absolutely  certain  that  no  other  possesses 
such  sensations  in  more  than  a  fractional  degree  of  ours.    What 


IS  NATURE  CRUEL?  411 

that  fraction  is  we  can  only  roughly  estimate  by  carefully  con- 
sidering the  circumstances  of  each  case.  These  show  that  it 
is  certainly  almost  infinitesimal  in  by  far  the  larger  part  of  the 
animal  kingdom,  very  small  in  all  invertebrates,  moderately 
small  in  fishes  and  reptiles,  as  well  as  in  all  the  smaller  birds 
and  mammals.  In  the  larger  of  these  two  classes  it  is  prob- 
ably considerable,  but  still  far  below  that  of  even  the  lowest 
races  of  man. 

A  Possible  Misconception 

It  may  be  said  —  I  fear  it  will  be  said  —  that  this  idea  of 
the  lower  animals  suffering  less  pain  than  we  suffer  will  Ix* 
taken  as  an  argument  in  favour  of  vivisection.     Xo  doubt  it 
will;  but  that  docs  not  in  the  least  affect  the  actual  truth  of 
the  matter,  which  is,  I  believe,  as  I  have  stated.      The  moral 
argument  against  vivisection  remains,  whether  the  animals  suf- 
fer as  much  as  we  do  or  only  half  as  much.     The  bad  effect 
on  the  operator  and  on  the  students  and  spectators  remains; 
the  undoubted  fact  that  the  practice  tends  to  produce  a  callous- 
ness and  a  passion  for  experiment,  which  leads  to  unauthorised 
experiments  in  hospitals  on  unprotected  patients,  remains;  the 
horrible  callousness  of  binding  the  sufferers  in  the  operating 
trough,   so   that   they  cannot   express  their   pain   by   sound   or 
motion,    remains;    their   treatment,    after    the    experiment,    by 
careless  attendants,  brutalised  by  custom,   remains ;   the  argu- 
ment of  the  uselessness  of  a  large  proportion  of  the   experi- 
ments,  repeated  again  and  again  on  scores   and   hundreds  of 
animals,   to   confirm   or   refute   the   work   of  other   vivisectors, 
remains ;   and,   finally,  the  iniquity  of  its   use  to  demonstrate 
already-established  facts  to  physiological  students  in  hundreds 
of  colleges  and  schools  all  over  the  world,  remains.      T  myself 
am  thankful  to  be  able  to  believe  that  even  the  hiijhest  animals 
below  ourselves  do  not  feel  so  acutely  as  we  do;  but  that  fact 
does  not  in  anv  wav  remove  mv  fundamental  disgust  at  vivi- 
section  as  being  brutalising  and  immoral. 


412  THE  WORLD  OY  LIFE 

A  Recent  Illustration  of  the  Necessity  of  Pain 

Within  the  last  few  years  we  have  had  remarkable  proofs 
of  the  beneficence  of  pain  as  a  life-saver  by  the  sad  results  of 
its  absence.  The  recently  discovered  X-rays,  so  much  used 
now  for  localising  internal  injuries,  and  of  bullets  or  other 
foreign  objects  in  any  part  of  the  body,  have  the  property  also 
of  setting  up  a  special  internal  disorganisation  unaccompanied 
at  the  time  by  pain.  The  result  has  been  loss  of  limbs  or  loss  of 
life  to  some  of  the  earlier  investigators,  and  perhaps  some  in- 
jury even  to  the  patients  for  whose  benefit  it  has  been  applied. 
It  seems  probable,  therefore,  that  if  these  rays  had  been  asso- 
ciated in  any  perceptible  degTce  with  the  heat  and  light  we  re- 
ceive from  the  sun,  either  the  course  of  evolution  would  have 
been  very  different  from  what  it  has  been,  or  the  development  of 
life  have  been  rendered  impossible.  Pain  has  not  accompanied 
the  incidence  of  these  rays  on  the  body,  because  living  organ- 
isms have  never  hitherto  been  exposed  to  their  injurious  effects. 

Microbes  and  Parasites:  their  Purpose  in  the  Life-World 

Much  light  is  thrown  on  the  analogous  problem  of  those 
human  diseases  which  are  supposed  to  be  caused  by  germs, 
microbes,  or  2:)arasites,  by  the  application  of  the  more  extended 
views  of  evolution  I  have  advocated  in  the  present  volume. 
The  medical  profession  aj^pear  to  hold  the  view  that  pathogenic 
or  disease-producing  microbes  exist  for  the  purpose  of  causing 
disease  in  otherwise  healthy  bodies  to  which  they  gain  access 
—  that  they  are,  in  fact,  wholly  evil.  It  is  also  claimed  that 
the  only  safeguard  against  them  is  some  kind  of  ^'  anti-toxin  " 
with  which  everv  one  must  be  inoculated  to  be  saved  from  the 
danger  of  attack  by  some  or  all  of  the  large  number  of  such 
diseases  which  affect  almost  every  organ  and  function  of  the 
body.  This  view  seems  to  me  to  be  fundamentally  wrong,  be- 
cause it  does  not  show  us  any  use  for  such  microbes  in  the 
scheme  of  life,  and  also  because  it  does  not  recognise  that  a 
condition  nf  health  is  the  one  and  only  protection  we  require 


IS  NATURE  CRUEL?  413 

against  all  kinds  of  disease;  and  that  to  put  any  product  of 
disease  whatever  into  the  blood  of  a  really  healthy  person  is  to 
create  a  danger  far  greater  than  the  disease  itself. 

On  the  general  principles  of  the  present  argunienr  there 
can  be  nothing  in  nature  which  is  not  useful,  and,  in  a  broad 
sense,  essential  to  the  whole  scheme  of  the  life-wtudd.  (Jn  this 
principle  the  purpose  and  use  of  all  parasitic  diseases,  including 
those  caused  by  pathogenic  germs,  i?^  to  seize  upon  the  less 
adapted  and  less  healthy  individuals  —  those  which  are  slowly 
dying  and  no  longer  of  value  in  the  preservation  of  the  species, 
and  therefore  to  a  certain  extent  injurious  to  the  race  by  recpiir- 
ing  food  and  occupying  space  needed  by  the  more  fit.  Tlicir 
life  is  thus  shortened,  and  a  lingering  and  unenjoyable  exist- 
ence more  speedily  terminated.  One  recent  writer  seems  to  hold 
this  view,  as  shown  by  the  following  passage: 

"  Before  it  was  perceived  that  disease  is  an  undisputable  battle- 
field of  the  true  Darwinian  struggle  for  existence,  the  tremendous 
part  which  it  takes  in  ridding  the  earth  of  weaklings  and  causing 
the  survival  of  health,  was  all  credited  to  the  environment  and  its 
dead  physical  forces."  ^ 

Bnt  in  this  interesting  article  the  writer  elsewhere  uses  lan- 
guage implying  that  even  the  healthy  require  rendering  ''  im- 
mune "  against  all  zymotic  diseases.  It  is  tliat  idea  which  I 
protest  against  as  a  libel  on  nature  and  on  the  Ruler  of  the 
Universe;  and  in  its  practice  as  constituting  a  crime  of  equal 
gravity  Avith  vivisection  itself. 

It  will  be  said  that  quite  healthy  persons  die  (^f  thesi^  dis- 
eases, but  that  cannot  be  proved;  and  the  absolutely  universal 
fact  that  it  is  among  those  living  under  unhealthy  conditions 
in  our  towns,  and  cities,  and  villages,  that  suft'er  most  from  these 
diseases  is  strongly  against  the  truth  of  the  statement.  No 
doubt  savage  races  often  suffer  drearlfully  from  these  diseases; 
but  savages  are  no  more  universally  healthy  than  the  more  civil- 

1  Parasitism  and  Natural  Sclrotioii.  l)y  R.  O.  Eccles,  M.D.,  Brooklyn,  N. 
Y.,  U.  S.  A. 


414  THE  WOELD  OE  LIFE 

ised,  though  it  is  usually  a  different  kind  of  unhealthiness. 
The  only  doctrine  on  this  matter  worthy  of  an  evolutionist,  or 
of  a  believer  in  God,  is  that  health  of  body  and  of  mind  are 
the  only  natural  safeguards  against  disease;  and  that  securing 
the  conditions  for  such  health  for  every  individual  is  the  one 
and  only  test  of  a  true  civilisation. 

A  few  words  in  conclusion  on  the  main  question  of  pain  in 
the  animal  world.  In  my  treatment  of  the  subject  I  believe  I 
have  given  imnecessary  weight  to  those  appearances  by  which 
alone  we  judge  of  pain  in  the  lower  animals.  I  feel  sure  that 
those  appearances  are  often  deceptive,  and  that  the  only  true 
guide  to  the  evolutionist  is  a  full  and  careful  consideration  of 
the  amount  of  necessity  there  exists  in  each  group  for  pain- 
sensation  to  have  been  developed  in  order  to  preserve  the  young 
from  common  dangers  to  life  and  limb  before  they  have  reached 
full  maturity.  It  is  exactly  the  same  argument  as  I  have  made 
use  of  in  discussing  the  question  of  how  mxuch  colour-sense  can 
have  been  developed  in  mammals  or  in  butterflies.  In  both 
cases  it  depends  fundamentally  on  utilities  of  life-saving  value 
as  required  for  the  continuance  of  the  race.  Hitherto  the  prob- 
lem has  never  been  considered  from  this  point  of  view,  the  only 
one  for  the  evolutionist  to  adopt.  Hence  the  ludicrously  exag- 
gerated view  adopted  by  men  of  such  eminence  and  usually 
of  such  calm  judgment  as  Huxley  —  a  view  almost  as  far  re- 
moved from  fact  or  science  as  the  purely  imaginary  and 
humanitarian  dogma  of  the  poet: 

The  poor  beetle,  that  we  tread  upon, 

In  corporal  sufferance  feels  a  pang  as  great 

As  when  a  giant  dies. 

Whatever  the  giant  may  feel,  if  the  theory  of  evolution  is 
true,  the  ''  poor  beetle  "  certainly  feels  an  almost  irreducible 
minimum  of  pain,  probably  none  at  all. 


CHAPTER    XX 

INFINITE    VARIETY    THE    LAW    OF    THE    UNIVERSE  CONCLUSION 

Throughout  the  present  work  I  have  liad  occasion  to  call 
attention  to  the  endless  diversity  that  characterises  both  organic 
and  inorganic  nature.  In  a  previous  work,  Man's  Place  in  the 
Universe,  I  was  impressed  by  the  diversity  which  the  new 
astronomy  had  shown  to  exist  throughout  the  stellar  universe. 
Since  that  book  was  written  such  remarkable  advance  has  been 
made  in  relation  to  the  nature  of  matter  itself,  as  to  constitute 
almost  a  new  science.  It  seems  desirable,  therefore,  to  say  a 
few  words  here  upon  the  whole  question  of  the  variety  and 
complexity  of  every  part  of  the  material  universe  in  its  rela- 
tion to  man  as  an  intellectual  and  moral  l:)eing,  thus  summaris- 
ing the  whole  aim  and  tendency  of  the  present  work. 

It  will,  I  think,  be  most  instructive  to  follow  the  same  order 
as  I  have  adopted  in  the  present  volume,  of  showing  how  each 
kind  of  variety  and  complexity  that  presents  itself  to  us  can 
be  traced  back  as  dependent  upon  a  preceding  complexity, 
usually  less  obvious  and  more  recently  brought  to  light.  Thus, 
the  most  obvious  of  all  the  diversities  in  nature  is  that  of  the 
various  forms  (or  kinds)  of  animals  and  plants ;  whereas  the 
diversities  of  inorganic  nature  —  stones,  rocks,  etc.,  are  far  less 
obvious,  and  were  discovered  at  a  much  later  period. 

The  Causes  of  the  Diversity  of  Life-forms 

Modern  research  shows  us  that  the  immense  diversitv  of  life- 
forms  we  now  find  upon  the  earth  is  due  to  two  kinds  of  causes, 
the  one  immediate,  the  other  remote.  The  iuimediate  cause 
is  (as  I  have  endeavoured  to  show  here),  the  slow  but  continu- 
ous changes  of  the  earth's  surface  ns  regards  contour,  altitude, 
climate,  and  distribution  of  land  and  water,  which  successively 

415 


416  THE  WORLD  OF  LIFE 

open  new  and  unoccupied  places  in  nature,  to  fill  which  some 
previously  existing  forms  become  adapted  through  variation 
and  natural  selection.  I  have  sufficiently  shown  how  this  proc- 
ess has  worked  throughout  the  geological  ages,  the  world's  sur- 
face ever  becoming  more  complex  through  the  action  of  the 
lowering  and  elevating  causes  on  a  crust  which  at  each  succes- 
sive epoch  has  itself  become  more  complex.  This  has  always 
resulted  in  a  more  varied  and  generally  higher  type  of  vegeta- 
tion, and  through  this  a  more  varied  and  higher  type  of  animal 
life. 

The  remote  but  more  fundamental  cause,  which  has  been 
comparatively  little  attended  to,  is  the  existence  of  a  special 
group  of  elements  possessing  such  exceptional  and  altogether 
extraordinary  properties  as  to  render  possible  the  existence  of 
vegetable  and  animal  life-forms.  These  elements  correspond 
roughly  to  the  fuel,  the  iron,  and  the  water  which  render  a 
steam-engine  possible;  but  the  powers,  the  complexities,  and 
the  results  are  millions  of  times  greater  in  the  former,  and  we 
may  presume  that  the  Mind  which  first  caused  these  elements 
to  exist,  and  then  built  them  up  into  such  man^ellous  living, 
moving,  self-supporting,  and  self-reproducing  structures,  must 
be  many  millions  times  greater  than  those  which  conceived  and 
executed  the  modem  steam-engine. 

Variety  of  Inorganic  Substances 

The  recognised  elements  are  now  about  eighty  in  number, 
and  half  of  these  have  been  discovered  during  the  past  century ; 
while  twenty  of  them,  or  one-fourth  of  the  whole,  have  been 
added  during  the  last  fifty  years.  These  last  are  all  very  rare, 
but  among  those  discovered  in  the  preceding  fifty  years  are 
such  now  familiar  and  important  elements  as  aluminium, 
bromine,  silicon,  iodine,  fluorine,  and  chlorine.  So  far  as  the 
elements  are  concerned,  our  earth  has  doubled  in  apparent  com- 
plexity of  structure  during  the  last  century.  But  if  we  take 
account  of  the  advance  of  chemical  science,  the  knowledge  that 
has  been  obtained  of  the  inner  nature  of  the  best-known  older 


THE  PURPOSE  OF  DIVEHSITY  417 

elements,  the  wonderfully  c'()ini)lr'x  laws  of  tlioir  combinations, 
and  the  immense  variety  of  their  known  eompounds,  our  ever- 
increasing  knowledge  of  the  complexity  of  matter  will  he  vory 
much  greater. 

During  the  early  part  of  the  nineteenth  century,  tlie  old 
idea  of  atoms  as  being  indivisible,  incompressible,  and  inde- 
structible particles,  almost  universally  prevailed.  They  were 
usually  supposed  to  be  spherical  in  form,  and  1<>  1m^  the  scat 
of  both  attractive  and  repulsive  forces,  leading  to  cohesion  and 
chemical  combination.  Those  of  the  different  elements  were 
supposed  to  differ  slightly  in  size,  and  energy,  which  led  to 
their  differences  of  weight  and  other  properties.  The  whole 
conception,  though  we  now  see  it  to  be  totally  inadequate,  was 
comparatively  simple,  and  with  the  help  of  the  mysterious  elec- 
tric and  magnetic  forces  seemed  capable  of  explaining  much. 

But,  decade  after  decade,  fresh  discoveries  were  made ;  chem- 
ical theory  became  more  and  more  complex;  electricity,  the 
more  it  was  known  the  less  intelligible  it  became ;  while  a  host 
of  new  discoveries  in  the  radiant  forces  of  the  ether  seemed  to 
show  that  this  mysterious  substance  was  really  the  seat  of  all 
the  forces  of  the  universe,  and  that  the  various  basic  forms  of 
matter  which  we  term  elements  were  nothing  more  than  the 
special  manifestation  of  those  forces.  It  thus  became  evident 
that  all  our  progress  in  physical  science  rendered  the  world  of 
matter  far  more  wonderful,  and  at  the  same  time  less  intel- 
ligible than  it  had  ever  seemed  to  us  before.^ 

1  The  progress  of  modern  chemistry  well  shows  this  increasing  com- 
plexity with  increasing  knowledge.  The  fact  of  carbon  existing  in  three 
distinct  forms  —  charcoal,  graphite,  and  diamond,  each  with  its  own  special 
physical  and  chemical  characters  —  has  already  been  referred  to.  Hut  it 
is  found  that  many  other  elements  have  similar  properties,  especially  sili- 
con, phosphorus,  arsenic,  antimony,  sulphur,  oxygen,  and  several  others. 
This  curious  property  is  termed  allotropy;  and  it  seems  somewhat  analo- 
gous to  that  property  of  many  compound  substances  termed  isomerism,  of 
which  two  striking  examples  were  given  at  tlie  beginning  of  the  last 
chapter.  Another  modern  braneh  of  chemistry  is  the  stuily  of  the  relation 
of  crystallised  substances  to  polarised  light,  which  reveals  nuiny  new  and 
strange  properties  of  identical  compounds,  and  is  termed  iStcrcochcmistry. 


418  THE  WORLD  OF  LIFE 

Eetuming  now  to  the  different  forms  under  which  matter 
exists  in  that  portion  of  the  earth  which  we  can  examine,  we 
find  them  to  be  very  limited  as  compared  with  those  of  the 
organic  world.  The  crust  of  the  earth,  and  presumably  the 
interior  also,  consists  mainly  of  what  are  called  minerals,  which 
is  the  term  used  for  all  chemical  compounds  of  the  elements 
which  have  been  produced  under  natural  laws  and  forces,  and 
constitute  the  materials  of  the  whole  planet.  They  comprise, 
besides  the  elements  themselves,  the  various  salts,  alkalis,  earths, 
metallic  ores,  precious  stones,  and  crystals,  which  have  a  def- 
inite chemical  constitution,  a  permanent  form,  and  definite 
characters ;  forming  what  are  termed  mineral  species.  These, 
when  disintegrated  by  natural  forces,  intermingled  in  various 
ways,  and  solidified  in  various  degrees,  make  up  the  whole  mass 
of  rocks  and  surface  material  of  the  earth.  The  total  number 
of  mineral-species  now  known,  almost  the  whole  of  which  are 
to  be  found  in  the  fine  mineralogical  gallery  of  the  British 
Museum,  is  almost  exactly  a  thousand.  Many  of  these  are 
very  rare  or  local,  the  great  bulk  of  the  rocks  being  made  up 
of  a  few  score,  or  at  most  of  a  few  hundreds  of  them. 

The  generally  accepted  idea  being  that  the  whole  earth  was 
once  a  molten  mass,  the  crust  may  be  supposed  to  give  a  fair 
sample  of  the  whole ;  and  the  additional  fact  that,  during  all 
geological  time,  matter  from  the  interior  has  been  brought  to 

These  various  properties  of  the  atoms  and  molecules  of  matter  have  so 
complicated  their  relations,  that  the  attempt  to  unravel  them  has  led  to  a 
system  of  equations,  of  diagrams,  and  of  formulae,  which  are  almost  as 
difficult  for  the  general  reader  to  follow  in  detail,  as  is  the  working  out  of 
some  abstruse  mathematical  investigation.  As  an  example  of  this  complex- 
ity in  chemical  nomenclature  I  may  refer  to  a  recent  paper  by  Sir  William 
Crookes,  on  the  rare  metal  scandium  (discovered  in  1879).  Near  the 
end  of  this  paper  (in  the  Proc.  Roy.  Soc,  series  A,  vol.  84,  p.  84),  the 
author  says :  "  By  the  kindness  of  Dr.  Silberrad,  I  have  had  an  oppor- 
tunity of  experimenting  with  octamethyltetraminodihydroxyparadixunthyl- 
bezonetetracarboxilic  acid." 

He  then  adds :  "  Previous  experiments  would  lead  one  to  expect  the 
scandium  salt  of  this  acid  to  have  the  composition  C44H4oOi4N4Se;.  The 
only    scandium    salt    I    could    form   with   this    acid    has    the    composition 

CssHjgOoaXsSCj. 


THE  PURPOSE  OF  DIVEESITY  419 

the  surface  by  volcanoes  and  liot  springs,  renders  it  prol>:d)lo 
that  very  few  either  of  the  elements  or  compounds  remain 
unknown. 

The  skill  of  the  chemist,  however,  has  led  to  the  production 
of  a  much  greater  number  of  stable  chemical  compounds  than 
occur  in  nature.  These  are  used  in  medicine  or  in  the  various 
arts,  and  their  numbers  are  very  great.  They  are  usually 
divided  into  two  classes,  the  inorganic  and  the  (jrganic;  the 
former  being  of  the  same  nature  as  tliose  of  the  great  bulk  of 
the  mineral  species,  while  the  latter,  called  also  carbon-com- 
pounds, resemble  the  products  of  living  organisms  of  which 
carbon  is  an  essential  part. 

A  recent  estimate  of  the  known  inorganic  compounds, 
natural  and  artificial,  bv  a  French  chemist  is  8000 ;  but  ^Ir. 
L.  Fletcher,  of  the  British  [Museum,  informs  me  that  this 
number  must  onlv  be  taken  as  an  ''  irreducible  minimum.'' 
As  to  organic  compounds,  I  am  told  by  Professor  II.  E.  Arm- 
strong, that  they  have  recently  been  estimated  at  about  100, 
000 ;  but  he  states  that  the  j^ossihilities  of  forming  such  com- 
pounds are  infinite,  that  chemists  can  make  them  by  thousand 
if  required,  and  that  they  now  limit  themselves  to  those  which 
have  some  special  interest.  The  approximate  figures  for  the 
various  kinds  of  stable  chemical  compounds  now  known,  will 
therefore  form  an  easily  remembered  series :  — 

Mineral  species 1 ,000 

Inorganic    compounds    (artificial) 10,000 

Organic  compounds    (artificial) 100,000 

Possible  organic  compounds Infinite! 

What  a  wonderful  conception  this  affords  us  of  the  possi- 
bilities of  the  elements  (or  rather  of  about  one-fifth  of  them) 
to  produce  the  almost  endless  variety  of  natural  products  in 
the  vegetable  and  animn!  kinirdoms.  Tliese  possibilities  must 
depend  upon  the  "properties"  of  the  elements;  not  only  their 
actual  properties  as  elements,  but  their  latent  pntperties 
through  which  they  not  only  combine  with  each  other  in  a 
great  variety  of  ways,  but,  by  each  eombi nation  create,  as  it 


420  THE  WOELD  OP  LIFE 

were,  a  new  substance,  possessing  properties  and  powers  dif- 
ferent from  those  of  any  other  substances  whatever.  These 
almost  infinitely  various  properties  of  chemical  combinations, 
together  with  a  host  of  other  problems  with  which  the  organic 
chemist  has  to  deal,  have  led  some  of  them  to  almost  exactly 
the  same  conclusion  to  which  I  have  been  led  by  a  more  super- 
ficial view  of  the  marvels  of  ''  growth  "  and  cell-division  in 
living  organisms.  In  the  Address  already  quoted,  Sir  H.  E. 
Armstrong  says,  after  referring  to  some  of  the  complex  and 
extraordinary  chemical  transformations  produced  by  living 
plants : 

"  The  general  impression  produced  by  facts  such  as  these  is, 
that  directive  influences  are  the  paramount  influences  at  work  in 
building  up  living  tissues." 

And  again  more  explicitly : 

"  It  would  seem  that  control  is  exercised  and  stability  secured 
in  several  ways;  not  only  is  the  form  laid  down  in  advance  but 
certain  chosen  materials  are  alone  available,  and  the  builders  can 
only  unite  particular  materials  in  particular  ways." 

It  is  very  satisfactory  to  find  that  both  chemists  and 
physiologists  recognise  the  absolute  need  of  some  controlling 
and  directive  power  in  elaborating  the  special  products  or 
building  up  the  complex  tissues  of  plants  and  animals. 

The  Cause  and  Purpose  of  this  Variety 

The  general  conclusion  to  which  the  whole  argument  of 
this  volume  tends,  is,  that  the  infinite  variety  we  see  in  nature 
can  be  traced  back  step  by  step  to  the  almost  infinite  complexity 
of  the  cells  by  means  of  which  they  live  and  gi'ow;  of  the 
protoplasm  which  is  the  substance  of  the  cells;  of  the  elements 
of  which  protoplasm  consists ;  of  the  molecules  of  those 
elements ;  and  finally  of  the  atoms  whose  combination  forms 
the  separate  and  totally  distinct  elementary  molecules.  And 
at  each  step  farther  back  we  are  as  far  ofi^  as  ever  from  com- 


THE  PUliPOSE  or  DlVEruSITY  421 

prehending  how  it  is  possible  for  such  infinite  diversity  to 
be  brought  about.  And  now  that  we  are  led  to  believe  that 
the  atom  itself  is  highly  complex  —  that  it  is  a  system  of  re- 
volving electrons  or  coi-puscles,  held  together  by  tremon«lous 
forces  —  the  mystery  becomes  deeper  still,  and  we  find  it  (piite 
hopeless  to  realise  what  is  the  nature  of  the  controlling  power 
and  mind,  Avhich  out  of  such  unimaginable  entities  lias  built 
up  the  vast  material  universe  of  suns  and  systems  of  which 
our  earth  foimis  a  fractional  part,  together  w^ith  that  even 
more  complex  world  of  life  of  which  we  ourselves  are  the  out- 
come. 

The  overwhelming  complexity  and  divei'sity  of  this  vast 
cosmos  in  its  every  part  and  detail,  is  the  great  fundamental 
characteristic  which  our  highest  science  has  brought  promi- 
nently to  our  notice ;  but  neither  science  nor  religion  has  given 
us  the  slightest  clue  as  to  why  it  should  be  so.  Science  says : 
"  It  is  so.  Ours  not  to  reason  why ;  but  only  to  find  out  what 
is.''  Religion  says :  "  God  made  it  so  " ;  and  sometimes  adds, 
"  it  was  God's  will ;  it  is  impious  to  seek  any  other  reason." 
In  the  present  work  I  have  endeavoured  to  suggest  a  reason 
which  appeals  to  me  as  both  a  sufficient  and  an  intelligible 
one:  it  is  that  this  earth  with  its  infinitude  of  life  and  beauty 
and  mystery,  and  the  universe  in  the  midst  of  which  we  are 
placed,  with  its  overwhelming  immensities  of  suns  and  nebuho, 
of  light  and  motion,  are  as  they  are,  firstly,  for  the  develop- 
ment of  life  culminating  in  man ;  secondly,  as  a  vast  school- 
house  for  the  higher  education  of  the  human  race  in  pn^jia ra- 
tion for  the  enduring  spiritual  life  to  which  it  is  destined. 

I  have  endeavoured  to  show  that  some  portion  at  least  of 
what  seems  a  superfluity  of  elements  in  our  earth-structure 
has  ser\'ed  the  purpose  of  aiding  the  gi'adual  progress  of  man 
from  barbarism  to  material  civilisation ;  while  another  portion 
has  furnished  him  with  materials  which  have  alone  enabled 
him  to  penetrate  into  the  two  unkninvn  worlds  with  which  ho 
was  encompassed  —  those  of  the  nlniost  infinitely  great  and 
of  the  almost  infiuitelv  little;   but  both   alike  attractive  an<l 


422  THE  WOELD  OF  LIFE 

grand  in  their  revelations;  both,  offering  ever-fresh  vistas  of 
unf athomed  mysteries ;  both  impressing  upon  him  the  existence 
of  immanent  forces  and  controlling  mind-power  as  their  only 
possible  cause. 

I  suggest,  further,  that  these  deeper  and  deeper  mysteries 
which  confront  us  everywhere  as  we  advance  farther  in  our 
knowledge  of  this  universe,  are  now  serving,  and  will  serve 
in  the  future  so  long  as  man  exists  upon  the  earth,  to  give 
him  more  and  more  adequate  conceptions  of  the  power,  and 
perhaps  to  some  extent  of  the  nature,  of  the  author  of  that 
universe ;  will  furnish  him  with  the  materials  for  a  religion 
founded  on  knowledge,  in  the  place  of  all  existing  religions, 
based  largely  on  the  wholly  inadequate  conceptions  and  be- 
liefs of  by-gone  ages. 

ft 

A  Suggestion  as  to  the  Origin  of  Life 

As  it  may  be  expected  that  I  should  state  what  is  my  ovm 
conception  of  the  power  which  I  claim  to  be  proved  to  exist, 
and  to  be  the  fundamental  cause  of  the  life-world  as  well  as 
of  the  material  universe,  I  will  here  make  a  few  suggestions 
as  to  what  seems  to  me  to  be  the  least  improbable,  the  least 
difficult,  of  all  attempts  to  deal  with  what  Herbert  Spencer 
held  to  be  "  unknowable,"  but  the  non-existence  of  which  he 
held  to  be  unthinkable.  In  the  Chapter  on  Religion,  in  Dar- 
win's Life  and  Letters,  he  also  seems  to  have  rested  in  the  one 
conclusion,  that  the  universe  could  not  have  existed  without  an 
intelligent  cause,  but  that  any  adequate  conception  of  the 
nature  of  that  cause  was  beyond  the  powers  of  the  human  mind 
to  form.  With  these  views  I  am  in  complete  sympathy;  but 
I  yet  think  that  we  can  form  some  conceptions  of  the  powers 
at  work  in  nature  which  help  us  to  overcome  the  insuperable 
difficulty  as  to  the  nature  of  the  infinite  and  absolute  creator, 
not  only  of  our  world  and  our  universe,  but  of  all  that  exists 
or  can  exist  in  infinite  space.  Here,  as  everywhere  in  science, 
we  must  not  attempt  to  deal  with  the  ultimate  problem  with- 


THE  PUKP08E  OF  DIVEKSITY  423 

out  studying  or  com2:)relieu(]iiig  the  steps  hy  which  it  may  be 
approached. 

I  venture  to  hope  that  in  the  present  volume,  and  especially 
in  the  last  six  chapters,  I  have  satisfied  most  of  my  rc^aders 
that  the  vast  life-world,  with  its  myriad  forms,  each  one 
originating  in  a  single  cell,  yet  growing,  by  cell-division,  into 
such  marvels  of  variety,  of  use,  and  of  beauty,  does  absolutely 
require  some  non-mechanical  mind  and  power  as  its  efficient 
cause.      To  such  onlv  mv  further  ar":ument  will  be  directed. 

My  first  point  is,  that  the  organising  mind  which  actually 
carries  out  the  development  of  the  life-world  need  not  bo  in- 
finite in  any  of  its  attributes  —  need  not  be  what  is  usually 
meant  by  the  terms  God  or  Deity.  The  main  cause  of  the 
antagonism  between  religion  and  science  seems  to  me  to  be 
the  assumption  by  both  that  there  are  no  existences  capable 
of  taking  part  in  the  work  of  creation  other  than  blind  forces 
on  the  one  hand,  and  the  infinite,  eternal,  omnipotent  God  on 
the  other.  The  apparently  gratuitous  creation  by  theologians 
of  a  hierarchy  of  angels  and  archangels,  with  no  defined  duties 
but  that  of  attendants  and  messengers  of  the  Deity,  perhaps 
increases  this  antagonism,  but  it  seems  to  me  that  both  ideas 
are  irrational.  If,  as  I  contend,  we  are  forced  to  the  assump- 
tion of  an  infinite  God  by  the  fact  that  our  earth  has  developed 
life,  and  mind,  and  ourselves,  it  seems  only  logical  to  assume 
that  the  vast,  the  infinite  chasm  between  ourselves  and  the 
Deity  is  to  some  extent  occupied  by  an  almost  inlinite  scries 
of  grades  of  beings,  each  successive*  grade  having  higher  and 
higher  powers  in  regard  to  the  origination,  the  development, 
and  the  control  of  the  universe. 

If,  as  I  here  suggest,  the  whole*  purport  of  the  material 
imiverse  (our  universe)  is  the  development  of  spiritual  beings 
who,  in  the  infinite  variety  of  their  natures  —  what  we  term 
their  characters, —  shall  to  some  extent  reflect  that  infinite 
variety  of  the  whole  inoriranic  and  orijanie  worlds  through 
which  they  have  been  developed;   and   if  we  further  suppose 


424  THE  WORLD  OF  LIFE 

(as  we  must  suppose  if  we  owe  our  existence  to  Deity)  that 
such  variety  of  character  could  have  been  produced  in  no  other 
way;  then  we  may  reasonably  suppose  that  there  may  have 
been  a  vast  system  of  co-operation  of  such  grades  of  being, 
from  a  very  high  grade  of  power  and  intelligence  down  to 
those  unconscious  or  almost  unconscious  ^'  cell-souls  "  posited 
by  Haeckel,  and  w^hich,  I  quite  admit,  seem  to  be  essential 
coadjutors  in  the  process  of  life-development. 

Xow  granting  all  this,  and  granting,  further,  that  each 
grade  of  being  would  be,  for  such  a  purpose  as  this,  supreme 
over  all  beings  of  lower  grade,  who  would  carry  out  their 
orders  or  ideas  with  the  most  delighted  and  intelligent  obe- 
dience; I  can  imagine  the  supreme,  the  Infinite  being,  fore- 
seeing and  determining  the  broad  outlines  of  a  universe  which 
w^ould,  in  due  course  and  with  efficient  guidance,  produce  the 
required  result.  He  might,  for  instance,  impress  a  sufficient 
number  of  his  highest  angels  to  create  by  their  will-power  the 
2:»rimal  universe  of  ether,  with  all  those  inherent  properties  and 
forces  necessary  for  what  was  to  follow\  Using  this  as  a 
vehicle  the  next  subordinate  association  of  angels  would  so  act 
upon  the  ether  as  to  develop  from  it,  in  suitable  masses  and 
at  suitable  distances,  the  various  elements  of  matter,  which, 
under  the  influence  of  such  laws  and  forces  as  gravitation, 
heat,  and  electricity,  would  thenceforth  begin  to  form  those 
vast  systems  of  nebulae  and  suns  which  constitute  our  stellar 
universe. 

Then  we  may  imagine  these  hosts  of  angels,  to  whom  a 
thousand  years  are  as  one  day,  watching  the  development  of 
this  vast  system  of  suns  and  planets  until  some  one  or  more 
of  them  combined  in  itself  all  those  conditions  of  size,  of 
elementary  constitution,  of  atmosphere,  of  mass  of  water  and 
requisite  distance  from  its  source  of  heat,  as  to  ensure  a 
stability  of  constitution  and  uniformity  of  temperature  for 
a  given  minimum  of  millions  of  years  or  of  ages,  as  would 
be   required   for   the   full   development   of   a    life-world   from 


THE  PURPOSE  OF  DiVEiiSiTY  425 

Amoeba  to  Man,   with  a  surplus  of  a  few  Inmdred   millions 
for  his  adequate  development. 

Thought-transference  as  an  agent  in  Creation 

In  my  Man's  Place  in  the  Universe  I  have  pointed  out 
the  very  narrow  range  of  the  quantitative  and  qualitativp  con- 
ditions which  such  a  world  must  possess ;  and  tlie  next  stop 
in  the  process  of  what  may  be  wtU  termed  "  creation  ''  would 
be  the  initiation  of  life  by  the  same  or  a  subordinate  body  of 
spirit-workers,  whose  duty  would  be,  when  the  waters  of  the 
cooling  earth  had  reached  a  proper  temperature  and  were 
sufficiently  saturated  with  gases  and  carbon-compounds,  to 
infuse  into  it  suitable  life-centres  to  begin  the  process  of  or- 
ganisation, which,  as  Huxley  acknowledged,  implies  life  as  its 
cause.  How  this  was  done  it  is  impossible  for  us  to  know, 
and  useless  to  speculate;  but  there  are  certain  guides.  From 
Haeckel's  concession  of  ^'  cell-souls  "  possessing  volition,  but 
a  minimum  of  sensation,  we  have  one  conceivable  starting- 
point.  From  Weismann's  vivid  description  of  cell-growth  and 
cell-division,  w-ith  its  complex  apparatus,  its  purposive  motions 
so  evidently  adapted  to  bring  about  a  definite  result,  and  its 
invariable  onward  march  to  that  result,  we  as  surely  imply 
an  intelligence  and  power  far  beyond  anything  we  know  or  can 
clearly  conceive. 

We  are  led,  therefore,  to  postulate  a  body  of  what  wo  may 
term  organising  spirits,  who  would  be  charged  with  the  duty 
of  so  influencing  the  myriads  of  cell-souls  as  to  carry  out  their 
part  of  the  work  with  accuracy  and  certainty.  In  the  power 
of  ^'  thought-transference  "  or  mental  impression,  now  gener- 
ally admitted  to  be  a  vera  causa,  possessed  by  many,  perhaps 
by  all  of  us,  we  can  understand  how  the  higher  intelligences 
are  able  to  so  act  upon  the  lower  and  that  the  work  of  the 
latter  soon  becomes  automatic.  The  work  of  the  organisers 
is  then  directed  to  keeping  up  the  supply  of  life-material  to 
enable  the  cell-souls  to  perform  their  duties  while  tlie  cells  are 
rapidly  increasing. 


426  THE  WORLD  OF  LIFE 

At  successive  stages  of  development  of  the  life-world,  more 
and  perhaps  higher  intelligences  might  be  required  to  direct 
the  main  lines  of  variation  in  definite  directions  in  accordance 
with  the  general  design  to  be  w^orked  out,  and  to  guard  against 
a  break  in  the  particular  line  which  alone  could  lead  ultimately 
to  the  production  of  the  human  form.  Some  such  conception 
as  this  —  of  delegated  powers  to  beings  of  a  very  high,  and  to 
others  of  a  very  low  grade  of  life  and  intellect  —  seems  to  me 
less  grossly  improbable  than  that  the  infinite  Deity  not  only 
designed  the  whole  of  the  cosmos,  but  that  himself  alone  is 
the  consciously  acting  power  in  every  cell  of  every  living  thing 
that  is  or  ever  has  been  upon  the  earth. 

What  I  should  imagine  the  highest  intelligence  engaged  in 
the  w^ork  (and  this  not  the  Infinite)  to  have  done  would  be 
so  to  constitute  the  substance  of  our  universe  that  it  would 
afford  the  materials  and  the  best  conditions  for  the  development 
of  life ;  and  also,  under  the  simple  laws  of  variation,  increase, 
and  survival,  would  automatically  lead  to  the  maximum  of  vari- 
ety, beauty,  and  use  for  man,  when  the  time  came  for  his  ap- 
pearance ;  and  that  all  this  should  take  place  with  the  minimum 
of  guidance  beyond  that  necessary  for  the  actual  working  of  the 
life-machinery  of  all  the  organisms  that  were  produced  under 
these  laws.  Some  such  conception  seems  to  me  to  be  in  har- 
mony with  the  universal  teaching  of  nature  —  everyw^here  an 
almost  infinite  variety,  not  as  a  detailed  design  (as  when  it 
was  supposed  that  God  made  every  valley  and  mountain,  every 
insect  and  every  serpent),  but  as  a  foreseen  result  of  the  con- 
stitution of  the  universe.  The  vast  whole  is  therefore  a  mani- 
festation of  his  powTr  —  perhaps  of  his  very  self  —  but  by 
the  agency  of  his  ministering  angels  through  many  descending 
grades  of  intelligence  and  power. 

Diversify  of  Human  Character 

Many  people  are  disturbed  by  the  now  w-ell-established  fact 
that  the  effects  of  use,  of  training,  or  of  education,  are  not 
inherited;   and  that  though  innate  mental   as  well   as  bodily 


THE  PURPOSE  OF  DIVEPSITY  427 

characters  vary  mucli  througli  inlieritanco  these  can  only  l)e 
developed  in  special  directions  hy  some  form  of  selection. 
There  being  very  little  if  any  effective  selection  of  character 
among  civilised  people,  they  therefore  fear  that  there  can  he 
no  continued  advance  of  the  race.  Quite  recently  1  have  dis- 
cussed this  question  from  two  points  of  view.  I^y  a  general 
glance  over  the  early  history  of  civilis.'d  man  1  have  shown 
that  there  is  little  if  any  evidence  of  advance  in  character  «h- 
in  intellect  from  the  earliest  times  of  which  we  have  anv 
record.^  I  had  already,  twenty  years  ago,  shown  in  some  d(»- 
tail  how,  under  a  rational  system  of  society,  in  which  all  the 
present  soul-degrading  influences  of  individualistic  wealth  and 
poverty  would  be  abolished,  (especially  as  leading  to  unholy 
marriages)  a  progressive  advance  in  character  would  neces- 
sarily arise  through  elimination  of  the  worst  and  most  degraded 
bv  an  effective  and  trulv  natural  selection.-  The  following 
passage  towards  the  end  of  the  former  article  will  briefly  indi- 
cate the  nature  of  the  argument  in  both  these  essays: 

"  The  great  lesson  taught  us  by  this  brief  exposition  of  the 
phenomena  of  character  in  relation  to  the  known  laws  of  organic 
evolution  is  this:  that  our  imperfect  human  nature,  with  its  almost 
infinite  possibilities  of  good  and  evil,  can  only  make  a  systematic 
advance  through  the  thoroughly  sympathetic  and  ethical  training 
of  every  child  from  infancy  upwards,  combined  with  that  perfect 
freedom  of  choice  in  marriage  which  will  only  be  possihle  wlien  all 
are  economically  equal,  and  no  question  of  social  rank  or  material 
advantage  can  have  the  slightest  influence  in  determining  that 
choice." 

It  now  only  remains  to  show,  verv  brieflv,  how  tlu^  views 
here  sketched  out  are  in  perfect  harmony  with  the  entire  scheme 
of  the  life-world.  That  scheme  is  shown  to  be  the  production 
of  an  almost  infinite  diversity  in  forms  of  life,  beautifuUv  eo 
ordinated  for  the  common  good,  and  for  the  ultimate  develop- 

1 "  Evolution  and  Character,"  Fortnijjhtly  Review.  January    1.   I'JOS. 
•-'"Human    Selection."    Fortni«ilit ly    Review.    Septj-niber    ISOl).     Reprinted 
in  Studies,  Scientific  and  Social,  1900,  vol.  i.  p.  509. 


428  THE  WORLD  OF  LIFE 

ment  and  education  of  an  almost  equally  varied  humanity. 
That  variety  has  been  assured  and  increased  by  the  rapid  de- 
velopment of  man  —  from  the  epoch  when  he  became  a  liv- 
ing soul  conscious  of  good  and  evil  —  so  far  above  the  beasts 
which  perish  that  there  was  little  actual  selection  except  to 
ensure  health  and  vigour,  and  the  gradual  advance  towards 
civilisation.  All  types  of  character  had  a  fairly  equal  chance 
of  survival  and  of  leaving  offspring,  and  thus  the  continued  un- 
checked action  of  the  universal  law  of  variation  led  to  an 
amount  of  diversity  of  human  nature  far  above  that  of  any 
of  the  lower  animals.  We  see  this  diversity  manifested  through 
all  the  ages,  from  the  lowest  depths  of  a  Nero,  a  Borgia,  or 
a  De  Eetz,  to  the  glorious  heights  of  a  Confucius  or  a  Buddha, 
a  Socrates  or  a  Newton. 

But  if  it  had  been  a  law  of  nature  that  the  effects  of  educa- 
tion should  be  inherited,  then  men  would  have  been  continually 
moulded  to  certain  patterns;  originality  would  have  been  bred 
out  by  the  widespread  influences  of  mediocrity  in  power,  and 
that  ever-present  variety  in  art,  in  science,  in  intellect,  in 
ethics,  and  in  the  higher  and  purer  aspirations  of  humanity, 
would  have  been  certainly  diminished.  And  if  it  be  said  that 
the  very  bad  would  have  been  made  better  if  educational  in- 
fluences had  been  inherited,  even  this  may  be  doubted;  for 
in  times  which  permitted  so  much  that  was  bad,  education 
often  tended  to  increase  rather  than  diminish  the  evil.  On 
the  other  hand,  w^e  are  more  and  more  coming  to  see  that  none 
were  all  bad,  and  that  their  worst  excesses  were  due  in  large 
part  to  the  influence  of  their  environment  and  the  fierce  temp- 
tations to  which  they  were,  and  still  are,  so  unnecessarily  ex- 
posed. 

But  it  is  when  we  look  upon  man  as  being  here  for  the 
very  purpose  of  developing  diversity  and  individuality,  to  be 
further  advanced  in  a  future  life,  that  we  see  more  clearly  the 
whole  object  of  our  earth-life  as  a  preparation  for  it.  In  this 
world  we  have  the  maximum  of  diversity  produced,  with  a 
potential  capacity  for  individual  educability,  and  inasmuch  as 


THE  PURPOSE  OF  DIVEPSTTY  420 

every  spirit  has  been  derived  from  tlio  Deitv,  onlv  liuiited 
by  the  time  at  the  disposal  of  each  of  us.  In  tlie  sj)ir it- 
world  death  will  not  cut  short  the  period  of  educational  ad- 
vancement. The  best  conditions  and  opportunities  will  be  af- 
forded for  continuous  progress  to  a  higher  status,  while  all 
the  diversities  produced  here  will  lead  to  an  infinite  variety, 
charm,  and  use,  that  could  probably  have  been  brought  about 
in  no  other  way. 

This  is  also  the  teaching  of  modern  spiritualism,  and  by 
this  teaching  its  existence  is  justified  and  its  truth  upheld. 
Such  teaching  pervades  all  its  best  literature,  of  which  Poe's 
Farewell  to  Earth,  given  through  the  trance  speaker  Miss 
Lizzie  Doten,  in  1863,  is  one  of  the  most  remarkable.^  He 
tells  us  of  the  educational  value  of  much  that  we  term  pain 
and  evil  in  the  following  lines : 

"  Gifted  with  a  sense  of  seeing. 
Far  beyond  my  earthly  being, 
I  can  feel  I  have  not  suffered,  loved,  and  hoped,  and  feared  in  vain; 
Every  earthly  sin  and  sorrow  I  can  only  count  as  gain, 
I  can  chant  a  grand  '  Te  Deum '  o'er  the  record  of  my  pain." 

Again,  he  shows  us  that  struggle  and  effort  are  essential 
for  progress  there  as  here : 

*^  Human  passion,  mad  ambition,  bound  me  to  this  lower  Earth, 
Even  in  my  changed  condition,  even  in  my  higher  birth. 
But  by  earnest,  firm  endeavour,  I  have  gained  a  height  sublime; 
And  I  ne'er  again  —  no,  never!  shall  be  bound  to  space  or  time; 
I  have  conquered!  and  for  ever!     Let  the  bells  in  triumph  chime! 
*  Come  up  higher  ' !  cry  the  Angels.     *  Come  up  to  the  Koyal  Arch ! 
Come  and  join  the  Past  Grand  Masters,  in  the  Soul's  progressive 

march, 
0  thou  neophyte  of  "Wisdom  !     Come  up  to  tlie  Poyal  Arch  !  '* 

1  Of  the  more  serious  books  tlealing  witli  tlie  ethics  and  j)liilosophy  of 
spiritualism,  I  will  only  direct  the  reader's  attention  to  two:  Spirit 
Teachings,  by  W.  Stainton  Moses,  M.A.;  aii.l  Psychic  Thilosophy,  as  the 
Foundation  of  a  Religion  of  Natiiral  Law.  hy  \'.  (,".  Desertes.  To  such 
of  my  readers  who  wisli  to  obtain  some  knowledge  of  the  higher  aspects  of 
modern  spiritualism,  I  strongly  reconunen«l  these  two  works. 


430  THE  WORLD  OF  LIFE 

In  the  preceding  verse,  however,  he  has  given  us  the  key- 
note to  the  future  life,  which  he  speaks  of  as  — 

The  land  of  Light  and  Beauty,  where  no  bud  of  promise  dies; 
and  then  continues  — 


iC 


There,  through  all  the  vast  Empyrean, 
Wafted,  as  on  gales  Hesperian, 
Comes  the  stirring  cry  of  '  Progress! '  telling  of  the  yet  to  be. 
Tuneful  as  a  seraph's  lyre, 
'  Come  up  higher !     Come  up  higher ! ' 
Cry  the  hosts  of  holy  angels :  '  learn  the  heavenly  Masonry : 
Life  is  one  eternal  progress :  enter  then  the  Third  Degree ;  — 
Ye  who' long  for  light  and  wisdom  seek  the  Inner  Mystery/  " 


Conclusion 

In  accordance  with  the  views  expounded  in  a  former  work, 
Man's  Place  in  the  Universe,  I  have  fully  discussed  the  evi- 
dences in  plant  and  animal  life  indicating  a  prevision  and  defi- 
nite preparation  of  the  earth  for  Man  —  an  old  doctrine, 
supposed  to  be  exploded,  but  which,, to  all  who  accept  the  view 
that  the  universe  is  not  a  chance  product,  will,  I  hope,  no 
longer  seem  to  be  outside  the  realm  of  scientific  inquiry. 

Still  more  important  is  the  argument,  set  forth  in  some 
detail,  showing  the  absolute  necessity  of  a  creative  and  directive 
power  and  mind  as  exemplified  in  the  wonderful  phenomena 
of  growth,  of  organisation,  and  fundamentally  of  cell-structure 
and  of  life  itself.  This  view  is  strengthened  by  a  considera- 
tion of  the  nature  of  the  elements  which  alone  render  life- 
development  possible. 

Herbert  Spencer  enforced  the  idea  of  "  variously  conditioned 
modes  of  the  universal  immanent  force  "  as  the  cause  of  all 
material  and  mental  phenomena,  and  as  the  "  Unknown  Reality 
which  underlies  both  Spirit  and  flatter."  I  have  here  ex- 
pressed  the   same  views   in   a  more   concrete   and   intelligible 


THE  PURPOSE  OF  DIVERSITY  431 

manner.  This  ^'  Unknown  Reality  "  is  necessarily  iiiiiiiitc  and 
eternal  as  well  as  all-knowing,  but  not  necessarily  what  we 
may  ignorantly  mean  by  ''  omnipotent  "  or  "  benevoleiii  "  in 
our  misinterjDretation  of  what  we  see  around  us.  1  have,  I 
hope,  cleared  aw^ay  one  of  these  misinter])r('tati<jns  and  mis- 
judgments  in  my  chapter  Is  Mature  (Jruel  ( 

But  to  claim  the  Infinite  and  Eternal  Being  as  the  one 
and  only  direct  agent  in  every  detail  of  the  uuiverse  seems, 
to  me,  absurd.  If  there  is  such  an  Infinite  Being,  and  if  (as 
our  own  existence  should  teach  us)  his  will  and  purpose  is 
the  increase  of  conscious  beings,  then  we  can  hardly  be  the 
first  result  of  this  purpose.  We  conclude,  therefore,  that  there 
are  now  in  the  universe  infinite  grades  of  power,  infinite  grades 
of  knowledge  and  wisdom,  infinite  grades  of  influence  of  liigher 
beings  upon  lower.  Holding  this  opinion,  I  have  suggested 
that  this  vast  and  wonderful  universe,  with  its  almost  infinite 
variety  of  forms,  motions,  and  reactions  of  part  upon  part, 
from  suns  and  systems  up  to  plant-life,  animal  life,  and  the 
human  living  soul,  has  ever  required  and  still  requires  the  con- 
tinuous co-ordinated  agency  of  myriads  of  such  intelligences. 

This  speculative  suggestion,  I  venture  to  hope,  will  appeal 
to  some  of  my  readers  as  the  best  aj^proximation  we  are  now 
able  to  formulate  as  to  the  deeper,  the  more  fundamental 
causes  of  matter  and  force,  of  life  and  consciousness,  and 
of  Man  himself;  at  his  best,  already  '^  a  little  lower  than  the 
angels,"  and,  like  them,  destined  to  a  permanent  progressive 
existence  in  a  World  of  Spirit. 


D.  H.  HILL  LIBRARY 
North  Carolina  Stat*  College 


INDEX 


Acidaspis  dufresnoyi,  288 
Adaptation,  some  aspects  of,  141 
Adaptations  to  drou<j;ht,  72;   binls 

and   insects,    143 ;    not   eflected   by 

use,  280;   of  plants,  animals,  ami 

man,  329 
A^Jlusmtrufi  felinus,  early  reptile,  215 
Agassiz,     a.,     on     deposition     by 

Mississippi,   192 
Allegory,  a  physiological,  319 
Allotropy  of  elements,  417 
Alpine  floras  not  exceptionally  rich, 

38,  40,  8G 
Amblypoda,    a    sub-order    of   Ungu- 

lata,  235 
America,  flora  of  tropical,  59 
American    bison,    former   enormous 

population  of,  124 
Ammonites,  eccentric  forms  of,  288 
Amceba,  description  of,  361 
Amphibia,  earliest  forms  of,  210 
Ancyloceras  matheronianum,  290 
Andrews,  Dr.  C.  W.,  discovers  an- 
cestral    forms     of     elephants     in 

Egj'pt,  245 
AnimalSj  numerical  distribution  of, 

89;  much  less  sensitive  than  man, 

405 

Anoplotherid.^,      ancestral      rumi- 
nants, 245 

Anoplotheriuin     commune,     skeleton 


of,  244 


recognition-marks     of, 


Antelopes, 

172 

ArchcBopteryx    macriira,    230;     sie- 

mensi,  skull  of,  231 
Arctic  lands  a  birds'  paradise,   151 
Argyll,    Duke    of,    on    humming- 
birds, 177 
Armstrong,     Professor    H.    E.,    on 
importance    of    carbon,    393:     on 
directive     influences     in     growth, 

420 
Arrhenius,    Professor,    uu    an    eter- 
nal universe,  379 
Arsinoitherium  zitteli,  skull  of.  240 
ASTROPOTiiERiA,    extinct    uniiulatcs, 

251 

433 


Atlantomxirua  immanis,  a  huge  dino- 
saur, 220 
Atoms,   early   ideas  of,   417 
Al'STRALIA,      extinct       tnainniMls      (if, 
25C 

Babirusa,  tusks  of,  29G 

Ballota  nigra,  local  distiiljiitioii  of, 
15 

Balsams,  dyes,  oils,  etc.,  variety  of, 
352 

Bate-Hardy,  ;Mr.  W.,  on  arrange- 
ment of  identical  atoms  in  carbon 
compounds,  384 

Beccari,  Dr.,  on  forest  flora  of 
Borneo,   56 

Beetle  mimicking  wasp,  169 

Beetles,  number  known,  91 ;  pecul- 
iar British,  135 

Being,  grades  of  between  us  and 
Deity,  423 

Bird,  earliest  known,  309 

Bird  and  insect  co-adaptation,  142; 
teachings  of,   164 

Bird's  wing,  the  ideal  aimed  at  in, 
308;  a  feather,  detailed  structure 
of,  309;   its  anniuil  regrowth,  311 

Bird-colour,  extreme  diversity  not 
of  survival  value  to  them,  344 

Bird-migRj\tion,   origin  of.    159 

Birds,  of  New  CJuinea  and  Borneo, 
53;  species  of,  93;  of  six  geo- 
graphical regions,  96;  peculiar  to 
Britain,  13.'),  13t):  arrival  of.  iti 
Arctic  regions.  151,  153:  number 
of  species  in  Arctic  region-^.  l.")7: 
recognition-marks  of.  175:  the 
earliest,  229;  recently  extinct. 
200:   loss  of  teeth   in  m'odern.  2;il 

Birds  and  insects,  proofs  of  or- 
ganising mind,  309 

l?iKi)S    OF    Parauisk,    new    types    of, 

2!)7 
Bison,    former   great    population    of 

in    America,    124 
BoLis.     Mr.    II..    on    flora    of    (  ape 

])eniii>^iila.  40:   on  orcliids  of  ('aj)e 

peninsula.  41 


434 


INDEX 


Borneo,    rich    forest    flora    of,    49; 

birds  of,  51 
Botanical,   reserves,   advantages    of 

small,  82 
BovERi's  experiments  on  echini,  373 
Brain-cavity    of    Dinocerata    very 

small,   239 
Brains  of  early  vertebrates,  small, 

291 
Brazil,,  richness  of  flora  of,  75 
Britain,      peculiar      animals      and 

plants  of,   135 
British    India,   flora  of,  47;    chief 

natural  orders  of,  48 
British   plants,  numerical  distribu- 
tion of,  24,  27;   of  limited  range, 

26 
Brittan,    Mr.    L.    K,    on    flora   of 

Jamaica,  67 
Brontosaurus   excelsus,   skeleton  of, 

221 
Butler,     Sir     W.,     on     mosquito- 
swarms,  146 
Butterflies,    recognition    by,    181, 

185 
Butterexy,    stages    of    development 

of,  325;  scales  on  wings  of,  325 
Butterfly  and  caterpillar,  diverse 

structure  of,  321 


Caltha  palustris,  wide  range  of,  19 

Cambrian  age,  first  known  life  of, 
207 

Campanula  isofpTiylla,  small  range, 
20 

Cape  Colony,  flora  of,  75 

Cape  peninsula,  rich  flora  of,  40 

Cape  Region,  rich  flora  of,  35,  77 

Carbon,  the  mystery  of,  390;  prop- 
erties of,  391;   in  the  ocean,  392 

Carnlvora,  early  forms  of,  240;  ex- 
tinct South  AmericaUj  249 

Cavies,  numerous  extinct,  252 

Celebes,  flora  of,  55,  85 

Cell,  the  mystery  of,  361;  charac- 
teristics of,  363;  implies  an  or- 
ganising mind,  364;  described  by 
Professor  Lloyd-Morgan,  364 ; 
Weismann's  description  of  a  di- 
viding, 365;  Weismann's  state- 
ment of  its  powers,  369 

Cell-problem,  concluding  remarks 
on,  376 

Ceratites  nodosus,  289 

Ceratosaurus  nasicornis,  skull  of, 
222 

Cetiosaurus  leedsi  from  Oxford  clav, 
220 


Challenger  voyage  defines  area  of 
deposition,  192 

Chemical  problems  of  water,  393; 
nomenclature,  illustration  of  com- 
plexity of,  418  *u 

China  and  Coreaj  flora  of,  34 

Christianity,  gradual  rise  of  a 
purer,  302 

Cities,  the  "wens"  of  civilisation, 
308 

CoaLj  wide  distribution  of  palaeo- 
zoic, 212;  prepared  atmosphere 
for  higher  life,  213 

Cobbett,  William,  on  "wens,"  308 

Cockerell,  on  tropical  species  as 
compared  with  temperate,  104 

Coleoptera,  number  of  British,  90; 
number  known,  91 

Colour,  for  concealment,  169;  ex- 
tremes of,  298;  of  flowers  sup- 
posed to  show  inedibility,  332; 
purpose  of  in  nature,  334;  of 
plants  and  animals  in  relation  to 
man,  340;  our  sensations  of,  an 
argument  for  design,  348,  349 

Colour-sense  not  identical  in  birds, 
mammals,  and  man,  325,  342 

Colours  of  butterflies,  uses  of,  183 

Colours  and  ornaments  of  males, 
how  caused,  282 

Compounds,  inorganic,  number  of, 
418;  number  of  organic  (artifi- 
cial), 419 

Condylarthra,  235 

Conocoryphe  sultzeri,  287 

Continental  extensions,  appendix 
on,  268;  great  difficulties  of,  269, 
270 

Continents,  how  built  up,  196,  198 

Coryphodon,  an  early  ungulate,  235 

Creators  of  matter  and  life  not 
necessarily  omnipotent,  422 

Creodonta,  early  carnivores,  242 

Crioceras  emerici,  289 

Crookes,  Sir  W.,  gives  an  example 
of  complex  chemical  nomencla- 
ture, 418 

Cruelty  of  nature,  supposed,  398 

Crustacea,  early  appearance  of, 
210 

D^dicurus,  giant  extinct  arma- 
dillo, 252 

Darwin  on  flora  of  a  very  small 
area,  87;  on  increase  of  elephant, 
123;  on  Porto  Santo  rabbits,  137; 
on  the  uses  of  colour  to  plants, 
329;  on  cross-fertilisation  of 
flowerSj    330;    on   war   of   nature. 


INDEX 


435 


399;    on   intelligent  cause  of  the 

universe,  422 
Darwinism,  extensions  of,  271 
Deane,  Mr.  H.,  on  flora  of  Sydney, 

New  South  Wales,  42 
De  Candolle,  a.,  on  botanical  gco^j;- 

raphy,    18,   24;    botanical   regions 

of,  20 
Definition  of  life,  3 
Denudation,  rate  of,  measured,  189 
Deposition,  area  of,  191 
Determinants,  meaning  of,  293 
Development,     reversal     of,     245; 

cases  of  extreme,  29G 
Diagram  of  human  stature,  116;  of 

variation     of     rice-bird,     118;     of 

nuclear  division,   370;    of  isomer- 
ism, 384 
Dicynodon  lacerticeps,  early  reptile, 

214 
Dimetrodon,    extinct    reptile    from 

Permian  of  Texas,  215 
Dinocerata,        "  terrible        horned 

beasts,"  236 

DiNOSAURIA,  217 

DiPLODOCUS,  skull  of,  222 

Diplodocus  carnegii,  skeleton  of, 
220 

Diprotodon  australis,  skull  of,  257 

DiPTERocARPS,  abundance  of  in 
Borneo,  56 

Directive  agency  not  explained  by 
Darwin's  *'  pan-genesis  "  nor  any 
other  theory,  319,  358;  indica- 
tions of,  354;  at  work,  373,  374 

Distribution  of  species  result  of 
continuous  adaptation,  103 

Domestic  animals,  uses  of,  305 

Dresser,  Mr.  H.  E.,  on  birds  breed- 
ing in  Arctic  regions^  155;  on 
mosquitoes  as  food  for  birds,   157 

Drosera  rotundifolia,  wide  range  of, 
18 

Drought,  adaptations  of  plants  to, 
72 

DwiNA  river,  rich  deposits  with 
early  reptiles,  214 

Earth's  surface  changes  a  cause  of 
evolution,  187 ;  thickness  of  crust 
of,  194;  crust  floats  on  melted  in- 
terior, 195;  eff'ect  of  cooling  ami 
contracting,  19G;  surface-motions, 
long  persistence  of,  200 ;  remlered 
habitable  by  water,  3!)6 
Eccentricity  in  nature,  298 
Eccles,  Dr.  R.  G.,  on  uses  of  par;i- 
sites,  413 


Echinus  microtuhcrculutus,  egi^  of, 
373 

Edentata,  extinct  S.  American,  252 

Educational  elTects.  unlimited  in 
tiie  spirit-worlfl.  4'JM 

Elements  in  nlalion  to  tiie  life- 
\\orI(l,  3S:{ :  important  and  unim- 
portant, 385;  list  of  important, 
38(i ;   in   iclation  to  man,  387 

Elephants,  rate  of  increase  of,  123; 
the  origin  of,  244 ;  diagram  of 
development  of,  24(1 

Elephas  gatusa,  enormous  tusks  of, 
287;  prim'ujcniuHy  .skeleton  of, 
249 

Eternity  as  explaining  evolution 
fallacious,  37!> 

European  floras  in  dilTerent  lati- 
tudes, 32;  compared,  36 

Evolution,  motive  power  of  or- 
ganic, 187 

Extensions  of  Darwinism,  271 

Extinction  of  pleistocene  mam- 
mals, cause  of,  261 

Feathers,  marvel  and  mystery  of, 
309 

Female  choice,  new  argument 
against,   184 

Ferns,  extreme  abundance  of,  in  the 
Philippines,  54 

Fishes,  peculiar  British,  135;  the 
earliest  known,  208;  types  of 
tails  of,  209 

Fletcher,  Mr.  L.,  on  inorganic 
compounds,  419 

Flight  of  birds  and  insects  com- 
pared, 94 

"  Flora  Orientalis,"  species  in.  34 

Flora  of  China,  34;  of  Chile,  35; 
of  Cape  region,  35;  of  tropical 
Asia,  46;  of  British  India,  47;  of 
;Malay  Peninsula,  47;  of  Borneo, 
49;  of  Indo-Ciiina,  50;  of  Malay 
Islands,  50;  of  New  C.uinea,  55; 
of  Philij)pine8,  54;  of  CeleU's,  55, 
85;  of  (.4)ueensland,  58;  of  trop- 
ical Africa,  59;  of  Madagascar, 
59;  of  tropical  America.  58,  59, 
()5 ;  of  lirazil,  63;  of  Mexico  luid 
Central  America,  64;  of  Jamaica, 
67;  of  Trinidaii,  67;  of  CJulapa- 
gos  Islamls.  67;  of  I^igoa  Santa. 
67,  77;  of  Penang,  79;  of  Kain- 
bangan  Islamls,  80;  of  Pange- 
ranifo.  81  ;  of  mountains  in  .la- 
pan.   SCf.   of  very   small   areas.  87 

I'l.ouAS  of  (liirercnt  regions  com- 
parctl.   11;    of   counties   compared. 


436 


IKDEX 


27 ;  of  some  parishes,  28 ;  of  small 
areas,  28,  77 ;  of  temperate  zones 
30;  cause  of  richness 
35;  warm  temperate 
compared,  3G;   of  European  small 

and 
86; 


compared, 
of     some. 


areas,     o/ ;      of     mountains 


plains     compared,     38,     40, 
extra-European  temperate,  39 

Flowering  plants,  peculiar  British, 
134 

Flowers,  al)undance  of,  within  Arc- 
tic circle,   153 

Food  of  young  birds,  142 

Forbes,  Mr.  H.  0.,  on  self-fertilisa- 
tion of  orchids,  332 

Forest  reserves,  advantages  of 
small  botanical,  79 

Fruits,  colour  of,  336 

Galapagos,  flora  of,  67 

Galton's  law  of  heredity,  110 

Gamble,  Mr.  J.  T.,  on  flora  of 
Malay  Peninsula,  47 

Gardner,  on  flora  of  Brazil,  77; 
on  supposed  greater  richness  of 
mountain  floras,  80 

Gatke,  Herr,  on  bird-migration  at 
Heligoland,  161 

Geese  moulting  in  Arctic  regions, 
148 

Gentiana  verna,  one  locality  in 
Britain,  26 

Geological  record,  account  of,  203; 
its  three  well-marked  periods, 
204;  the  teaching  of.  300 

Geology,  as  influencing  evolution, 
188 

Germinal  selection,  281,  292,  296 

Glass  essential  for  science,  338 

(ilyptodon  clavipes,  skeleton  of,  253 

Glyptodontid.e,  extinct  armadillos, 
252 

Grant  Allen  on  insects  and  colour 
of  flowers,  333 

Grey  plover's  nest  in  Arctic  re- 
gions, 156 

Griesbach,  on  Mediterranean  flora. 
34;  on  Brazilian  flora,  76 

Growth,  the  nature  of,  315;  by  cell- 
division,  316;  admitted  to  be  in- 
explicable, 371;  by  cell-division, 
what  it  implies. 
Dr.,  on 


Gunther, 
94 

Haeckel 
human 

ether,   7, 
scions. 


373 
species 


of  birds. 


on    consciousness,    o ;     on 

nature,     6;     matter     and 

,8;    on   soul-atom   uncon- 

358;    his   carbon-theoiv   of 


life,  391 


Hamites  rotundity,  290 

Hardy,  Mr.  W.  B.,  on  complexity  of 
proteid  molecule,  383 

Hartert,  Dr.,  on  peculiar  British 
birds,  135 

Hayati,  Mr.,  on  floras  of  Japanese 
mountains,  39,  40 

Heat,  rate  of  increase  in  deep  bor- 
ings, 194 

Heligoland  and  migrating  birds, 
160 

Hemsley,  W.  B.,  on  flora  of  Central 
America,  61 

Heredity  a  universal  fact,  109; 
Galton's  law  of.  110 

Heteroceras  etnerici,  289 

Hooker,  Sir  Joseph,  on  flora  of 
British  India,  47;  on  primary 
floras,  65;  on  rich  flora  of  Pe- 
nang,  77;  on  floras  of  very  small 
areas,  87 

Horns  as   recognition-marks,   173 

Horses,  extinct  South  American, 
250 

Hudson,  W.  H.,  on  field  mice  in 
Argentina,  132 

Human  character,  diversity  of.  426 

Hutton,  Capt.,  on  recognition- 
marks,  178 

Huxley,  Professor,  on  nature  and 
origin  of  life.  9;  on  matter  and 
spirit,  10;  on  crueltv  of  nature, 
400 

Hycenodon  cruentus,  skeleton  of, 
242 

Hyopotamns  hrachyrhynchns,  skele- 
ton of,  243 

Ichthyopterygia,  223 

Ichthyosaurus,  paddles  of,  224 

Ichthyosaurus  communis,  skeleton 
of,  224 

Iguanodon    hemissartensis, 
of,  218;  skull  of,  219 

Increase    in    plants    and 
121 

Indo-China,  estimate  of  flora  of,  50 

Inheritance  of  educational  results 
would  have  checked  diversity,  427 

Inorganic  substances,  varietv  of, 
416 

Inostransevia,  huge  carnivorous 
reptile,  skull  of,  2l6 

Insect  life  of  secondary  period,  228 

Insect  pests,  uses  of,   142 

Insects,  known  species  of,  91;  pe- 
culiar to  Britain,  135;  earliest 
known.  211;  and  their  metamor- 
phosis, 321 


skeleton 
animals, 


i:tTDEX 


437 


Insects  and  birds,  co-adaptation  of, 

143 
Irish  deer,  skeleton  of,  287 
Isomerism  explained,  385 

Jack-rabbit,    E.    S.    Thompson    on, 

172 
Jamaica,  flora  of,  67 
Japan,  mountain  floras  of,  40 
Java,  rich  flora  of,  80 
JoRDAX,  Dr.   K.,   on   phosphorescent 

colours  in  lepidoptera,  347 
JuDD,    Professor,    on    strange   forms 

of  ammonites,  87 

Kambangan  island,  rich  flora  of,  80 
Karoo  formation,  reptiles  of,  213 
Kearton  on  increase  of  rabbits,  122 
Kerner,    Dr.    A.,    on    power    of    in- 
crease of  plants,   121 ;   on  the  in- 
sect  enemies   of   flowers,   331 ;    on 
"vital    force/'    356;    on    arrange- 
ment   of    atoms    in    the    carbon- 
compounds,  384 
KooRDERS,    Dr.,    on    the    flora    of 
Celebes,  55,  85;   on  rich  floras  of 
small  areas  in  Java,  79 

Lagoa  Santa,  flora  of,  67,  75 

Land-shells,  peculiar  British,   135 

IjAtitude  as  influencing  floras,  31 

Lemming,  periodical  migrations  of, 
128-30 

Lepidoptera,  number  of  British,  89 ; 
number  known,  91 ;  peculiar 
British,  135;  wealth  of  colour  in, 
345-47 

Life,  definition  of,  3 ;  Haeckel  on, 
4,  7 ;  the  cause  of  organisation, 
8;  reactions  of  animal  and  plant, 
304 ;  the  sole  cause  of  life,  306 ;  a 
suggestion  as  to  origin  of,  422 

Life-deveix)pment  of  mesozoic  era, 
231;  conclusion  on,  299 

Life-forms,  causes  of  diversity  of, 
415 

Life-world,  progressive  development 
of,  203 

Limestone,  progressive  increase  of, 
234 

lAthospermiim  gastoni,  narrow  range 
of,  19 

Llamas,  extinct   S.   American,   240 

Lloyd-Moroan,  statement  of  theory 
of  germinal  selection,  292;  on 
rapid  cell-growth,  375 

Ltdekker,  jSIr.,  on  Patagonian  mar- 
supials,    241;     on     affinities     of 


American  and  Australian  marsu- 
pials, 265 
Lyell,  Sir  C,  on  causes  of  extinc- 
tion, 264 
London,  how  to  stop  growth  of,  308 
LowNE,  Mr.  B.  T.,  on  development 
of  blow-fly,  323 

Machcerodus  neogcpua,  skull  of,  286 

Macrmichenia  patachonica,  251 

Macroscaphiies  ivanii,  290 

Madagascar,  flora  of,  59 

M cerifherium   lyonsi,  skull  of,  244 

Malay  Islands,  flora  of,  50;  in- 
sects of,  92 

Malay  Peninsula,  table  of  chief 
orders  of  plants,  47 ;  character- 
istic plants  of,  48 

Mammalia,  teachings  of  pleistocene, 
265 

Mammals,  extinct  Australian,  256 

Man,  the  cause  of  extinction  of 
pleistocene  mammals,  268-70;  the 
glory  and  distinction  of,  402-06; 
the  most  sensitive  of  organisms, 
409 

Mantell,  Dr.,  discovered  extinct 
reptiles  in  Kent,  217 

Marsh,  Professor  O.  C,  on  Bronto- 
saurus,  220;  on  Dinocerata,  237; 
on  small  brains  of  early  mam- 
mals, 239;  causes  of  extinction  of 
mammals,  263 

Marsupials  in  Patagonian  miocene, 
240;  of  the  Australian  type  still 
living  in  the  Andes,  264 

Martius's  flora  of  Brazil,  63 

Mastigophora,  362 

Mastodon  in  S.  America,  254 

Mastodon  americanus,  skeleton  of, 
247 

Mastodons,  less  developed  ele- 
phants, 246 

Max  Verworu  on  chemistry  of  pro- 
toplasm, 316;  on  vital  force,  317 

Mediocrity,   recession  towards,    117 

^Mediterranean  flora,  species  in,  34 

Megatherium,  extinct  ground  sloth, 
252 

Megatlierium  giganteum,  restoration 
of,  254 

Mendelism  and  mutation  inefficient 
as  substitutes  for  Darwinian  evo- 
lution, 133 

]\rKRRiLL,  Mr.  E.  D.,  on  flora  of  the 
Pliilii)pines,  54 

Mesozoic  era,  213;  mammalia  of, 
228:  insects  of,  228;  life-develop- 
ment of,  231 


438 


INDEX 


Metals,  the  seven  ancient,  387;  es- 
sential for  civilisation,  388 

Metamorphosis  of  insects,  321 

Mexico  and  Central  America,  flora 
of,  64 

Microbes,  use  of  in  nature,  412 

Migration,  origin  of  bird,  159; 
facts  and  inferences,  160-63 

Mimicry,  169 

Minahassa,  N.  Celebes,  flora  oF,  55, 
85 

Mind  and  purpose  in  life-develop- 
ment, 299 ;  and  life,  different  de- 
grees of,  307;  produces  brain,  307 

Minerals,  number  of  species  of, 
418 

Mivart,  St.  George,  on  recognition- 
marks,   179 

Morgan,  Professor  L.,  on  germinal 
selection,  292;  on  rapid  cell- 
growth,   375 

Mosquitoes,  uses  of,  145;  descrip- 
tion of  Arctic,  146;  food  for  most 
young  birds,  151 

Mosses  and  hepaticse,  peculiar 
British,  135 

Mountain  floras,  in  Japan,  40;  not 
richest,  97 

MtJLLER  on  insect-fertilisation  of 
flowers,  333 

Mylodon,  contemporary  of  man, 
254 

Mylodon  rohii^tus,  skeleton  of,  254 


Narwhal's  tusk  an  extreme  devel- 
opment, 296 
Natural  selection,  illustrative  cases 

of,    134;    of    sparrows    at    Ehode 

Island,   138;   process  of  at   Porto 

Santo,  138 
Nature,  the  sanctity  of,   301;   our 

defacement  of,   301;    is   it  cruel? 

398 
New    Guinea,    biologically    unique, 

51 ;    flora  of,   55 :    richness   of  its 

bird  fauna,  96,  98 
Newton,  Professor  A.,  on  passenger 

pigeon,  128 
North   American  floras  in  various 

latitudes,  34 
Nototherium,     extinct     Australian 

wombat,  260 
Nuclear  division,  diagram  of,  370 
Nucleus,  importance  of,  373 
Nummulites,  363 
Nuts,    why    intended    to    be    eaten, 

337 


Ocean,  carbon  in,  392 

Orchids,  abundance  of  in  Cape 
Peninsula  and  New  South  Wales, 
41 ;   in  British  India,  48 

Okeodontid.e,  early  American  rumi- 
nants, 242 

Organising  spirit  the  cause  of  life- 
production  and  control,  425 

Organs,  beginnings  of  new,  271 

Ornithosaltiia,  224 

Pain,  its  purpose  and  limitations, 
398;  a  product  of  evolution,  404; 
beneficent  purpose  of,  412;  where 
useless  does  not  exist,  413;  in  na- 
ture, Huxley's  exaggerated  view 
of,  400,  414 
Pal.eomastodons,    early    elephants, 

244-45 
Palceotherium   magnum,    restoration 

of,  244 
Paleozoic  era  described,  206 
Palms,  abundance  of  in  the  Malay 
Peninsula,  47;  in  the  Philippines, 
54 
Pangerango,  Mount,  rich  flora  of, 

81 
rarndoxides  hohemicus,  287 
Pariasaurus  hainii,  skeleton  of,  214 
Passenger  pigeon  now  extinct,  125; 
enormous  population  of  less  than 
a  century  ago,   125 
Penang,  rich  flora  of,  79 
Phascolotherium,  231 
Phenacodiis  primcBvus,   early   ungu- 
late, 235 
Philippines,  rich  flora  of,  54 
Physiological  allegory  on  growth, 

319 
Plant-cell,  Kerner  on,   371;   iden- 
tity with  animal  cell,  372 
Plants    of    wide    distribution,    21; 
abundance    of    compared,    23;    of 
very  small  areas,  numbers  of,  98 
Pleistocene    mammalia,    teachings 

of,  259 
Plesiosaurus  macrocephalus,  skeleton 

of,  222 
PoE,    extracts    from    supposed    im- 

pressional  poem  by,  428 
Porto  Santo  rabbits,  newly  formed 

species,  137 
Potentilla  rupestris,  one  locality  in 

Britain,   27 
PouLTON,  Prof.  E.  B.,  on  beginnings 

of  new  organs,  272 
Primates,    fossil    species   of    South 
America,  249 


i:n^dex 


439 


Primula  imperialis,  small  range,  19 

Proteid  molecule,  complexity  of, 
383 

Prothylacinus,  a  Patagonian  mar- 
supial, 240 

Protoplasm,  its  chemical  nature, 
315 

Pteranodon  occidentalis,  skeleton  of, 
226;   longiceps,  skull  of,  227 

Pterodactyl,  restoration  of  long- 
tailed,  22G 

Pterodactylus  spectahilis,  skeleton 
of,  225 

Ptychoceras  emeridanum,  290 

Purpose  of  our  universe  to  produce 
variety  of  human  character,  299, 
421 

Pyrothebia,  251 

Queensland,  flora  of,  58 

Rabbits,  increase  of  in  Australia, 
123 

Radiolaria,  362 

Radium,  its  rarity  and  uses,  389 

Ramsay,  Sir  A.,  on  life  of  the  Cam- 
brian age,  207 

Recognition  by  butterflies,  181 

Recognition-marks  important  for 
evolution,  168;  explained,  170; 
objection  to  answered,  178;  gen- 
eral conclusions  on,  185 

Religion,  gradual  rise  of  a  true, 
302 

Reptiles,  earliest,  214 

Reptilian  life  of  secondary  period, 
227 

Retrogressive  development  in 
birds,  309 

Rhizopoda,  362 

Rice-bird,  diagram  of  variation  of, 
118 

Ridley,  Mr.,  on  flora  of  Singapore, 

79 
River-basins,  rate  of  denudation  of, 

189 
Roscoe,    Sir    H.,    on    properties    of 
carbon,  388;  on  water  in  relation 
to  life,  391 

Saleeby,  Dr.,  on  eternity  as  an  ex- 
planation, 379 

Sap,  extreme  production  of,  299 

Sauropterygia,  223 

Scales  on  wings  of  buttciilics,  .'l-i.")  -. 
apparent  purpose  of,  327 

Scelidosaurus  harrisoni,  skeleton  of. 
218 


Sceloditherium  leptocephalum,  skel- 
eton of,  255 

ScLATER,  Dr.  P.  L.,  on  species  of 
birds,  94 

Seeboiim,  H.,  on  food  of  birds  in 
Arctic  regions,   146 

Seton-Tiiompson  on  recognition- 
marks,  172 

SiiARPE,  Dr.  B.,  on  species  of  birds, 
94 

Shipley,  A.  E.,  table  of  described 
animals,  99 

Simethis  bicolor,  one  locality  of  in 
Britain,  27 

Singaporp:,  flora  of,  79;  destruction 
of  forest  in,  85 

Sisymbrium  sophin,  power  of  in- 
crease of,  121 

Small-brained  animals,  purpose  of, 
306 

South  Africa,  Cape  Region,  flora 
of,  79 

South  America,  tertiary  mammals 
of,  249 

Spalacotherium,  229 

Sparrows  at  Rhode  Island,  work  of 
natural   selection  on,    138 

Species  defined,  12;  distribution  of, 
13;  uncertainty  of  limits  of,  25; 
rarity  of  precedes  extinction,  26; 
number  of,  in  relation  to  evolu- 
tion, 100;  variation  of.  113;  ex- 
tremely common,  114;  to  be  seen 
everywhere,  115 

Spencer,  H.,  on  co-ordination  of 
variations,  275;  reply  to,  276, 
277;  his  "  unkno^^^l  reality" 
more  concretely   expressed,   430 

Spirit-life  described  (inspiration- 
ally)    by  Poe,  428 

Springbok,  curious  recognition- 
mark  on,  174 

Spruce,  Dr.,  on  rich  flora  of  Ama- 
zon, 61 

Sterrolophus  fJabeJIatus,  skull  of, 
219 

Stone-curlews,  recognition  marks 
of,   175 

Sydnetx",  extreme  abundance  of  or- 
chids near,  41 

Table  of  De  Candolle's  botanical 
regions,  20;  of  chief  natural 
orders  in  various  floras,  22;  of 
number  of  species  in  large  and 
small  areas.  28;  of  numln^r  of 
species  in  difTerent  latitudes,  31: 
of  floras  of  European  oonntries 
according     to     latitude,     31;     of 


440 


INDEX 


floras    of   XortH   American   areas, 
32;    of   warm  temperature   floras, 
36;    of   European   floras   of   small 
areas,      37;      of      extra-European 
temperate     floras,     39;     of     large 
tropical  floras,  45;  of  chief  orders 
of  flora  of  British   India,   47;    of 
chief    orders    of    tropical    Sikkini. 
48;     of     chief     orders     of     Malay 
peninsula,  48;    of  chief  orders  of 
the   Philippines,    54;    of   chief   or- 
ders of  Celebes,   56;    of  chief  or- 
ders of  Madagascar,  59;   of  chief 
orders      in      tropical      American 
floras.  64 ;  of  chief  orders  of  Mex- 
ico and  Central   America,   65;    of 
chief     orders     of     Nicaragua     to 
Panama,    67;    of   chief    orders    of 
Lagoa    Santa,    71;    of   number    of 
species  in  tropical  floras  of  small 
area,  77 ;  of  number  of  species  in 
temperate    floras    of    small    area, 
77;   of  distribution  of  lepidoptera 
in  Britain,  89;   of  distribution  of 
coleoptera,       90;       of      described 
species   of  orders   of    insects,    91; 
of  species  of  birds  in  Europe,  95; 
of  species  of  birds  in  zoological  re- 
gions, 96;   of  described  species  of 
living  animals,  99;  of  percentage 
of  mean  error  of  variation.   121 ; 
of  peculiar  sub-species  of  British 
birds,  136;  of  rate  of  lowering  of 
river-basins,  189 

Teeth,  gradual  loss  of  during  de- 
velopment, 291 

Temperate  floras  compared,  30,  36, 
39;   floras,  small  areas,   77 

Temperature  -  adjustments  of 
earth's  surface.  202 

Tertiary  period,  life  of,  235 

Tetrabelodon,  restoration  of,  245 

Tetrahelodon  angustidens,  skeleton 
of,  246 

Theriomorpha,  beast-like  reptiles 
of  Karoo  formation,  S.  Africa, 
213 

Thompson,  E.  Seton,  on  recogni- 
tion-marks, 172 

Thomson,  Prof.  J.  A.,  on  deter- 
minants, 293;  on  mechanics  of 
the  germ-plasm,  370;  on  nature's 
stern  methods,  399 

Thought-transference  the  agent 
in  life-production  and  guidance, 
425 

Thylacoleo  carnifex,  skull  of,  258 


Titanotherium  rohustum,  skeleton 
of,  238 

Toxodon  platensis,  skeleton  of,  250 

TOXODONTIA,  251 

Truchycerafiaon,  289 

Tkicoxodon,  229 

Tkilobites,  early  and  late  forms 
of,  287 

Tkixiuad,  flora  of,  68 

Thopical  floras  of  the  world,  43;  of 
large  areas  compared,  45;  small 
areas,  77 

Tropical  and  temperate  vegetation 
compared,   105 

Thopical  vegetation,  causes  of  rich- 
ness of,   106 

Tylor,  a.,  on  rate  of  denudation, 
189 

Uintatherium  ingens,  skeleton  of, 
236;   cornutum,  skull  of,  237 

Ungulata,  early  forms  of,  235; 
extinct  South   American,  249 

Universe,  purpose  of  the  stellar, 
299  ' 

Upheaval  produced  by  contraction, 
197 

Variation  of  mind  as  great  as  of 

body,   114;   as  shown  in  curve  of 

stature.  116;  of  the  various  parts 

of  a  bird,  118 
Variation  of  species,  113 
Variations,  co-ordination  of,  275 
Variety  in  nature,  purpose  of,  300; 

the    law    of    the    universe,    415; 

cause  and  purpose  of,  420 
Vegetable   products   in   relation  to 

man,  350 
Vegetation,   differences   of   tropical 

and  temperate,   105;   early,  210 
VernoNj    Dr.    H.    M.,   on   variation, 

119;     on    parts    of    human    body 

varying   independently,    120 
Vertebrates,    special     features    in 

development  of,  291 
Vital  force.  Max  Verworu  on,  316; 

Dr.  A.  Kerner  on,  356 

WARiiiNG,  Professor  Eug.,  on  flora 
of  Lagoa  Santa,  67,  74 

Water  in  relation  to  life,  394;  com- 
plex problems  of,  395;  as  prepar- 
ing earth  for  man.  397 

Weismann's  theorv  of  germinal  se- 
lection, 292 

Weymouth,  abundance  of  ammon- 
ites at.  288 


INDEX 


441 


Wilson,  Alexander,  on  numbers  of 
passenger  pigeons,  125,  126 

Winter  transformed  into  summer, 
153 

Wood,  various  qualities  of,  352 

Woodrufffc-Peacock  on  detailed 
floras,  15;  on  meadow  and  pas- 
ture plants,   17 

Woodward.  Dr.  A.  S.,  on  progress- 
ive developments  of  some  charac- 


ters, 285;  on  small  brains  of  early 
vertebrates,  270 
Wulfenia    carinthiaca,    small    range 
of,  19 

X-RAYS  prove  use  of  pain,  411 

Zoological  regions,  species  of  birds 
in,  96 


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